fast
/fɑːst/ (bre, ipa) · [fˈæst] /fæst/ (ame, ipa) · [fˈæst] /ˈfast/ (ame, mw)
fast — adjective
- fastpositive
- fastercomparative
- fastestsuperlative
1. achieving high speed or done in little time — a fast athlete moves quickly, a fa
achieving high speed or done in little time — a fast athlete moves quickly, a fast process finishes swiftly, and a fast answer comes without delay.
Tuan took a fast train from Taipei to Kaohsiung that reached over 250 km/h.
fast + noun describing a physical object
The company saw fast growth in its first year of business.
Eli is the fastest runner on the school team and wins every race.
Maeve needed a fast answer, so she called instead of sending an email.
Christopher made a fast recovery after breaking his arm in the fall.
- quick
very similar in meaning; 'quick' often emphasises short duration ('quick shower') while 'fast' emphasises high speed ('fast car')
- rapid
more formal than 'fast'; commonly used with processes and changes ('rapid population growth')
- swift
slightly more literary; suggests smooth, effortless speed ('swift response')
- speedy
informal; focuses on completion without delay ('speedy delivery')
- slow
the direct opposite for speed and duration
文法句型
fast + noun (car, train, growth)
be + fast
用法筆記
This is the most common sense of 'fast' and applies to physical speed (vehicles, people), rate of change (growth, progress), and short duration (response, recovery).
常見錯誤
❌ 'He is a fast learner' (acceptably correct) — note that 'fast' here describes the person's ability, not their physical speed.
2. used when a timepiece gives a reading that is ahead of the actual moment — for i
used when a timepiece gives a reading that is ahead of the actual moment — for instance, a clock showing 8:03 when the real time is 8:00 is said to be three minutes fast.
Sade's watch is five minutes fast, so she always arrives early for class.
number + minutes/hours + fast
Erik noticed the classroom clock was fast and told the teacher about it.
If your phone clock is fast, you might show up before the movie starts.
The timer on the oven runs fast, so Camila set it ten minutes behind.
- ahead
less common for clocks; 'the clock is ahead' means the same but is much rarer
- slow
showing a time earlier than the correct time
文法句型
clock / watch + be + fast
run + amount + fast
用法筆記
Only used for timekeeping devices (clocks, watches, timers). Not used for calendars or schedules. The opposite is 'slow'.
常見錯誤
3. describing photographic film or camera equipment that responds well in dim condi
describing photographic film or camera equipment that responds well in dim conditions, allowing you to capture sharp images even with little illumination or of subjects that are moving.
Hiro bought fast film for taking pictures at the indoor concert.
fast + film
A fast lens helps you take clear photos in low light without a flash.
fast + lens
Sports photographers use fast shutter speeds to capture moving athletes.
The camera's fast sensor captured each feather on the flying bird.
- high-speed
slightly broader; 'high-speed film' and 'fast film' are interchangeable
- sensitive
describes the light sensitivity directly but is less specific to photography than 'fast'
- slow
slow film or slow lens requires more light
文法句型
fast + noun (film, lens, shutter)
用法筆記
Mainly used in photography contexts. A 'fast' lens has a wide aperture (small f-number) that lets in more light. 'Fast' film has a high ISO number.
4. full of quick action, excitement, and rapid changes; describing an experience, p
full of quick action, excitement, and rapid changes; describing an experience, place, or activity that feels energetic and never slows down.
Sumin enjoys fast action movies with car chases and fight scenes.
fast + action movie / pace
Life in a big city is fast and can feel stressful at first.
be + fast describing lifestyle
The video game's fast pace kept the players focused for many hours.
Élise loves the fast atmosphere of the newsroom where she works.
- lively
positive and less intense; suggests enjoyable energy rather than pressure ('lively discussion')
- hectic
more negative; suggests stressful, chaotic busyness ('hectic schedule')
- high-energy
informal; emphasises excitement and intensity
- slow-paced
describes something that moves at a relaxed or leisurely rate
- relaxed
the opposite of a fast, stressful environment
文法句型
fast + noun (pace, life, city)
be + fast
用法筆記
Describes experiences, lifestyles, and entertainment — not physical speed of an object. A 'fast movie' means it has lots of action, not that it plays at high speed.
5. living in a way that others consider morally careless, especially by seeking too
living in a way that others consider morally careless, especially by seeking too much pleasure or by being sexually unrestrained — this meaning is dated and often sounds disapproving.
The novel tells the story of a fast social crowd in 1920s New York.
Evelyn's grandmother warned her about spending time with a fast crowd downtown.
fast + crowd / set / life
In old films, a fast woman was a character who broke social rules.
The newspaper described the party as fast and full of wild behaviour.
- wild
broader and less judgmental; can describe energetic fun without moral criticism ('wild party')
- promiscuous
specifically about sexual behaviour; more clinical and neutral in tone
- dissolute
formal and literary; describes someone who lives without moral restraint
文法句型
fast + noun (crowd, woman, life)
用法筆記
This sense is dated and carries a strong disapproving tone. Avoid using it to describe people directly in modern conversation — it can sound rude or judgmental. Limited mostly to historical or literary contexts.
常見錯誤
6. used for a dye or pigment that stays in the fabric it was applied to, so it does
used for a dye or pigment that stays in the fabric it was applied to, so it does not run, fade, or wash away when the item is cleaned or left in the sun.
Camila checked the label to see if the red dress was colour-fast.
compound: colour-fast
The dye on these jeans is fast, so you can wash them with other clothes.
Cyrus bought a rug with colours that stay fast even in bright sunlight.
Always wash new dark clothes in cold water until the colour is fast.
- colour-safe
a commercial term; 'colour-safe bleach' won't damage fast colours but the term isn't used for the fabric itself
- fade-resistant
more modern and specific; commonly used for outdoor fabrics ('fade-resistant paint')
- fading
losing colour over time
文法句型
colour / dye + be + fast
用法筆記
Often used in the hyphenated compound 'colour-fast' (or 'color-fast' in American English). Common on clothing labels and washing instructions. The opposite is 'the colour runs'.
7. securely attached or held in position; not easily moved, loosened, or changed —
securely attached or held in position; not easily moved, loosened, or changed — often used for physical objects that are stuck or tied firmly.
The cupboard door was fast and would not open no matter how hard Liam pushed.
be + fast describing a stuck object
The painter made sure the ladder was fast before climbing to the roof.
During the storm, all the windows were checked to make sure they were fast.
Padma tied a double knot to keep the rope fast around the tree trunk.
- secure
broader; can describe safety from danger as well as firm attachment ('secure knot')
- firm
general-purpose; used for both physical and figurative stability ('firm grip')
- tight
suggests physical pressure keeping something in place ('tight lid')
- stuck
informal; emphasises that something cannot be moved ('stuck window')
文法句型
be + fast
hold + object + fast
stick + fast
用法筆記
Frequently paired with verbs such as 'hold', 'stick', 'stay', 'keep', and 'make'. In the phrase 'hold fast', 'fast' can be read as an adverb describing how the holding is done — the boundary between adjective and adverb is blurry in this sense.
常見錯誤
fast — adverb
1. at great speed; in a way that takes very little time — for example, running fast
at great speed; in a way that takes very little time — for example, running fast, driving fast, or learning fast.
The children ran as fast as they could to catch the school bus.
as fast as + clause
Evelyn learns fast and finished the training course in just two weeks.
verb + fast (learn, work, think)
Please drive as fast as you safely can — we are already late.
Karim's heart was beating fast after the run up the steep hill.
- slowly
at a low speed; taking a long time
文法句型
verb + fast
as fast as
用法筆記
The adverb form of 'fast' is identical to the adjective — there is no word 'fastly'. Use 'fast' after action verbs (run, drive, work, learn, grow).
常見錯誤
2. in a firmly fixed or securely attached way; with strong determination not to mov
in a firmly fixed or securely attached way; with strong determination not to move or change position.
The soldiers stood fast against the enemy attack all through the night.
stand fast — fixed phrase for physical or moral resistance
Hiro held fast to his dream of becoming a doctor despite the challenges.
hold fast to — figurative: keep believing in
The boat was stuck fast in the mud when the tide went out.
Ife held fast to the railing as the train moved through the tunnel.
- loosely
not firmly; with slack or give
文法句型
hold + fast
stand + fast
stick + fast
用法筆記
This adverb sense appears in three main fixed phrases: 'hold fast' (physical grip or figurative commitment), 'stand fast' (refuse to change position or opinion), and 'stick fast' (physically unable to move). Unlike the 'quickly' adverb sense, this one cannot be used freely with other verbs.
常見錯誤
fast — noun
- fastsingular
- fastsplural
1. a stretch during which someone deliberately eats very little or nothing at all,
a stretch during which someone deliberately eats very little or nothing at all, often for religious, spiritual, health-related, or medical reasons.
During Ramadan, Muslims observe a daily fast from sunrise to sunset.
observe a fast — formal/religious use
Yasmin went on a three-day fast to help clean out her body.
go on a fast — start a fasting period
Some people break their fast with a light meal of soup and bread.
The doctor warned that a long fast can be dangerous without drinking water.
文法句型
a + (number) + fast
break + one's + fast
go on + a + fast
用法筆記
Often used with the verbs 'observe', 'keep', 'break', and 'go on'. The word 'breakfast' literally means 'breaking the fast' after a night of sleep.
常見錯誤
fast — verb
- fastpresent simple I / you / we / they
- fasts3rd person singular
- fasting-ing form
- fastedpast simple
1. to go without eating on purpose over a set stretch, typically for religious obse
to go without eating on purpose over a set stretch, typically for religious observance, health reasons, or medical preparation.
Cyrus fasts for sixteen hours every day as part of his diet plan.
fast + for + duration
Many Christians fast during the season of Lent before Easter Sunday.
fast during + period (religious observance)
The patient had to fast for twelve hours before the blood test.
Mira felt dizzy after fasting for the whole day without drinking any water.
- feast
to eat a large, elaborate meal, often in celebration
文法句型
fast + for + period of time
fast + from + time + to + time
用法筆記
This verb is intransitive — you do not fast 'something'. You fast for a period of time or from a specific time. To describe what you avoid, use 'fast from + food/drink' (e.g., 'fast from meat').