lock-up

IPA/lˈɒkˈʌp/
IPA/lˈɑːkˈʌp/

lock-up — phrasal verb

  • lock-upbase form
  • lock-ups3rd person singular
  • lock-uping-ing form
  • lock-upedpast simple

1. to close and fasten all the locks on the entrances and windows of a building, ma

1.phrasal verbtransitive / intransitiveB1
Definition

to close and fasten all the locks on the entrances and windows of a building, making it safe when nobody is inside

Example

Élise always locks up the shop before she goes home for the night.

lock up + shop / office / house (building nouns)

The last person to leave the office should lock up and set the alarm.

intransitive use: “lock up” without an object

Common collocations
  • lock up the shop / office / house / warehouse / apartment
  • lock up for the night
  • lock up before leaving
Synonyms
  • secure

    more formal; used in official instructions (“Secure the premises before leaving”)

  • bolt

    more specific to sliding a metal bar across the door; less common in everyday speech

  • shut up

    informal British usage (“Shut up the shop”); avoid confusion with “shut up” meaning stop talking

Antonyms
  • open up

    to unlock and open a building for the day

  • unlock

    to open a lock, undoing the action of locking

Grammar Patterns

lock up [noun phrase]

lock [noun phrase] up

lock up (intransitive)

Usage Note

Can be used without an object when the building is clear from context (“Who locked up last night?”). The object (the name of the building) often goes between “lock” and “up” in short sentences: “lock the house up” or “lock up the house.”

Common Mistakes

I locked the keys up inside the car.
I locked the keys in the car.
“lock up” means securing a building, not accidentally trapping something inside a vehicle.

2. to put someone in prison or in a confined space such as a cell, so that they can

2.phrasal verbtransitiveB1
Definition

to put someone in prison or in a confined space such as a cell, so that they cannot leave

Example

The judge ordered that the burglar be locked up for at least three years.

passive: “be locked up for [duration]”

In some countries, journalists are still locked up for reporting the truth.

passive: “be locked up for [reason]”

Common collocations
  • lock someone up in prison / in a cell
  • lock someone up for a crime / for years
  • be locked up without trial
Synonyms
  • imprison

    more formal and official; used in legal writing

  • incarcerate

    very formal; used in official or academic contexts

  • jail

    similar register; common in news reporting (“He was jailed for five years”)

Antonyms
  • release

    to set someone free from prison

  • free

    more general; can mean to let someone out of any confinement

Grammar Patterns

lock [someone] up

be locked up

be locked up in [place]

be locked up for [crime / duration]

Usage Note

Commonly used in the passive voice (“was locked up”) when the police or authorities are the understood but unstated subject. In informal contexts, can also refer to restricting someone to a room (“They locked the child up in her bedroom as punishment”), but the primary meaning is imprisonment.

Common Mistakes

The police locked up the criminal.
The police locked the criminal up.
Both forms are correct; the separable form sounds more natural in short sentences. Focus on getting the object in the right place rather than avoiding the structure.

3. to store something valuable, important, or dangerous inside a lockable container

3.phrasal verbtransitiveB1
Definition

to store something valuable, important, or dangerous inside a lockable container or room so that it cannot be stolen or accessed by others

Example

Anong took off her wedding ring and locked it up in her bedside drawer.

lock [thing] up in [container]

The lawyer told us to lock up the original contracts in a fireproof safe.

lock up + documents / contracts / valuables

Common collocations
  • lock up money / jewellery / documents / passport / medicines / chemicals
  • lock up in a safe / drawer / cupboard / cabinet / locker
Synonyms
  • lock away

    very similar meaning; “lock away” often implies putting something out of reach for good

  • store

    more general; does not necessarily involve a lock

  • secure

    formal; used in official instructions about handling valuables or documents

Antonyms
  • take out

    to remove something from its locked storage

Grammar Patterns

lock up [noun phrase]

lock [noun phrase] up

lock [noun phrase] up in [container]

Usage Note

Distinguish from sense 1 (SECURE BUILDING) — sense 3 refers to putting a specific item inside a lockable space, not to securing an entire building. The preposition “in” is frequently used to specify the container: “lock up the money in a box.”

Common Mistakes

I locked up my bag.
I locked my bag up in the locker.
The verb alone does not explain where the item is stored; add a location with “in” to make the meaning clear.

4. to invest money in a way that makes it impossible or very costly to get the cash

4.phrasal verbtransitiveB2
Definition

to invest money in a way that makes it impossible or very costly to get the cash back before a fixed date

Example

The pension plan locks up workers’ savings until they turn sixty.

lock up + savings / capital / funds

Folake was warned that the new fund would lock her money up for at least five years.

lock [money] up for [duration]

Common collocations
  • lock up capital / savings / funds / money
  • lock up money in bonds / real estate / a fund / a pension plan
  • lock up for a period of years
Synonyms
  • tie up

    a slightly less formal alternative; “My money is tied up in the business”

  • freeze

    stronger; suggests that money cannot be moved at all, often by court order

Antonyms
  • release

    to make invested money available again (“release the funds”)

  • withdraw

    to take money out of an account or investment

Grammar Patterns

lock up [money / capital]

be locked up in [investment]

lock [money] up for [period]

Usage Note

Restricted to formal financial contexts. The subject is usually a financial product (fund, plan, bond) or an investor. Never refers to physical locking — the “lock” here is metaphorical, describing a contractual restriction on withdrawing money.

Common Mistakes

I locked up some shares last Thursday.
My investment plan locks up my money for ten years.
“lock up” in the financial sense describes a structural restriction, not a one-time action of buying.

Synonym discussion

Sense: phrasal verb/1

These words all relate to making a building safe, but differ in how common and how specific they are. “Lock up” is the most frequent everyday phrasal verb for closing and locking all the doors and windows of a building. “Lock away” has a similar meaning but is more often used for storing individual items (locking documents away in a safe) rather than securing a whole building. “Bolt” describes pushing a metal bar across the door — a specific action that is part of locking up but not a replacement for the full routine. “Secure” is more formal and official; you might see it in workplace instructions (“Secure the premises”). “Shut up” is informal British English for closing a shop for the day (“We shut up at seven”), but it can cause confusion with the unrelated meaning “stop talking.” For everyday conversation about making a building safe, “lock up” is the best all-purpose choice.

lock away ↗bolt ↗secure ↗shut up ↗

Etymology

Old EnglishMiddle EnglishModern English

The verb “lock” comes from Old English “loc”, meaning a fastening device or barrier. The particle “up” adds a sense of completeness — locking something up means locking it fully, not just partly. The phrasal verb first appeared in Middle English with the literal meaning of securing a door or building. By the early 1800s, “lock up” was being used figuratively for putting a person in prison. The financial meaning — making money hard to withdraw — developed in the mid-1900s, drawing on the same idea of confinement.