facultative
facultative — adjective
- facultativepositive
- more facultativecomparative
- most facultativesuperlative
1. describes a power, right, or clause that allows someone to do something without
describes a power, right, or clause that allows someone to do something without forcing them to; related to giving permission or official authority.
The contract contained a facultative clause that let the buyer cancel the order within thirty days.
collocation: facultative clause
Under facultative authority, the manager could approve urgent expenses without waiting for the board.
collocation: facultative authority
The treaty gave each nation a facultative right to withdraw from the agreement after five years.
Noor argued that facultative powers should be written into the new company rules.
A facultative provision in the law allows cities to set their own tax rates if they choose.
- permissive
suggests tolerance rather than active granting of power
- enabling
stronger implication of making action possible
- authorizing
more direct and active act of granting permission
- restrictive
imposes limits rather than granting freedom
- prohibitive
actively forbids rather than permits
文法句型
facultative + noun (power, authority, right, clause, provision)
用法筆記
Frequently appears in legal and formal contexts paired with nouns such as clause, right, authority, power, and provision.
常見錯誤
2. not required; something a person can choose to do, take part in, or use, without
not required; something a person can choose to do, take part in, or use, without any penalty for skipping it.
Attendance at the Friday seminar was facultative, so only a few students came.
pattern: facultative + noun (attendance)
The school offered several facultative courses in photography and music.
Participation in the research study was facultative, and everyone who joined signed a form.
Jenna chose two facultative modules alongside her four required subjects.
Wearing a uniform was facultative at the summer camp, so most children wore their own clothes.
- compulsory
required by rule or law
- mandatory
required by official order
- obligatory
required by duty or custom
文法句型
facultative + noun (course, subject, attendance, module)
用法筆記
More formal than optional. Common in academic and institutional contexts. After facultative, the noun must be countable (course, module, activity), not a gerund.
常見錯誤
3. relating to a natural ability of the mind, such as memory, reasoning, imaginatio
relating to a natural ability of the mind, such as memory, reasoning, imagination, or will — used in older philosophy that treats the mind as a set of separate powers, each with its own job.
In his work On the Soul, Aristotle described memory as a distinct facultative power separate from other mental abilities.
collocation: facultative power
Thomas Aquinas divided the mind into several facultative domains, including intellect, will, and memory.
Tendai wrote about facultative abilities such as planning and judgment in her thesis.
Bonaventure wrote that memory, understanding, and will are three facultative powers reflecting the soul's structure.
Duns Scotus called the human will the most important facultative power because it can choose freely.
- cognitive
modern, preferred term in psychology; facultative is historical or philosophical
- mental
broader and more common in everyday speech
- intellectual
focuses on reasoning rather than all mental abilities
文法句型
facultative + noun (power, ability, domain, function)
用法筆記
Almost exclusively found in historical or philosophical discussions of the mind. In modern psychology, cognitive is the preferred term.
4. describes a biological trait or behavior that happens only when particular envir
describes a biological trait or behavior that happens only when particular environmental conditions are met, rather than always occurring — for example, a species that hibernates only during harsh winters.
The frog is a facultative hibernator, sleeping through winter only when temperatures drop very low.
collocation: facultative hibernator
Some plants are facultative perennials, living for one year in cold areas but for many in warm ones.
Pim studied a fish species that uses facultative air-breathing, gulping oxygen only in stagnant water.
Bird migration in this region is facultative, taking place only when food becomes hard to find.
The tree disease is facultative, harming the plant only when the soil stays wet for too long.
- conditional
broader term, not specific to biology
- contingent
emphasizes dependence on prior conditions
- circumstantial
suggests influence of surrounding circumstances
- obligate
biology term meaning always occurring or always required
- unconditional
not limited by any conditions
文法句型
facultative + noun (hibernator, perennial, migration)
用法筆記
Contrasts with obligate, which means always happening or always required. Facultative organisms or traits switch on or off depending on conditions.
常見錯誤
5. describes a living thing that can switch between fundamentally different ways of
describes a living thing that can switch between fundamentally different ways of feeding, breathing, or living, depending on its environment — for example, an organism that can survive with or without oxygen, or with or without a host.
Unlike true parasites, this worm is a facultative parasite that can survive without a host.
collocation: facultative parasite
The bacteria are facultative anaerobes, able to live both in oxygen and without it.
collocation: facultative anaerobe
Lucía identified the insect as a facultative social species, forming groups only at high population density.
This orchid is a facultative epiphyte, growing on trees in wet forests but rooting in soil where needed.
The algae are facultative heterotrophs, making their own food in sunlight but absorbing nutrients in the dark.
- adaptable
general term; facultative is specific to biology
- flexible
everyday word for ability to change
- non-obligate
direct contrast to obligate in biology
- obligate
must live a certain way — e.g., obligate parasite cannot survive without a host
文法句型
facultative + noun (parasite, anaerobe, social species, epiphyte)
用法筆記
Distinguish from sense 4: sense 4 describes a single trait or behavior that depends on conditions (e.g., hibernation, migration), while sense 5 describes the organism's overall lifestyle strategy — what kind of feeder or dweller it is.