constrain

constrain — verb

1. to put a limit on how something can develop, be done, or change — for example, w

1.verbtransitiveB2
Definition

to put a limit on how something can develop, be done, or change — for example, when a shortage of money stops a school from hiring enough teachers, or when rules control what companies are allowed to do.

Example

The drought severely constrained the amount of food that local farmers could grow.

constrain + noun phrase (amount of food)

It was frustrating for the team to be constrained by such tight deadlines.

passive: be constrained by [deadline/limit]

Common collocations
  • constrained by budget
  • constrained by time
  • severely constrained
  • tightly constrained
  • constrained environment
Synonyms
  • restrict

    More common in everyday English; used especially for rules and physical limits

  • limit

    The broadest and most common word; covers any boundary on size, amount, or ability

  • curb

    More formal; suggests actively holding something back, often something undesirable

Antonyms
  • free

    To remove limits or restrictions

  • liberate

    To set free from constraints, often in a broader or more formal sense

Grammar Patterns

constrain + noun phrase

be constrained by + noun phrase

Usage Note

Frequently used in the passive voice. The subject is typically an external factor such as a budget, law, space, or rule — not a person who actively restricts someone. Common in formal, academic, and professional writing.

Common Mistakes

The new dress code constrained employees to wear formal clothes.
The new dress code required employees to wear formal clothes.
'constrain' is about limiting options, not about stating a simple requirement.
She constrained the door with a heavy lock.
She secured the door with a heavy lock.
'constrain' is not used for physically locking or blocking something in everyday English.

2. to put pressure on someone so that they must act or choose in a certain manner b

2.verbtransitiveB2
Definition

to put pressure on someone so that they must act or choose in a certain manner because of a rule, promise, duty, or set of circumstances — for example, when a contract obliges a business to deliver goods by a certain date, or when a promise stops someone from sharing secret information.

Example

The contract constrained Pim to deliver the goods by the end of March.

constrain + pronoun + to-infinitive

Judges are constrained to apply the law exactly as it is written.

passive: be constrained to + infinitive

Common collocations
  • constrained to act
  • constrained by duty
  • constrained by promise
  • feel constrained to
  • contractually constrained
Synonyms
  • force

    Stronger and more direct; can describe personal or physical pressure

  • compel

    Similar register to 'constrain'; often used in legal or formal contexts

  • oblige

    Less strong; suggests duty rather than strict limitation of choice

Antonyms
  • free

    To release from an obligation or limitation

  • release

    To let someone go from a duty or promise

Grammar Patterns

be constrained to + infinitive

feel constrained to + infinitive

Usage Note

Most common in the passive voice followed by a to-infinitive ('be constrained to do something'). The agent of the constraint is usually an obligation, promise, contract, or circumstance — not typically another person. 'Feel constrained to' adds a sense of personal reluctance.

Common Mistakes

Her parents constrained her to study every evening.
Her parents forced her to study every evening.
'constrain' is not typically used with a person as the active agent of pressure; use 'force' or 'make' instead.
I constrained him to come to the party.
I persuaded him to come to the party.
'constrain' implies a serious limitation of choice, not casual persuasion.

Word family

  • constraint
    nounB2
  • constrained
    adjectiveB2
  • constraining
    adjectiveC1
  • unconstrained
    adjectiveC1

Synonym discussion

Sense: verb/1

'Constrain', 'restrict', 'limit', and 'curb' all describe putting a boundary on something, but they differ in formality and focus. 'Limit' is the most common and general word — you can limit the number of guests, the speed of a car, or the time allowed for a test. 'Restrict' is more common in everyday English for rules or physical boundaries that control what people can do, such as restricting access to a building. 'Constrain' is more formal and often used in professional or academic contexts to describe forces that narrow possibilities or options — for example, when a tight budget constrains a department's hiring plans. 'Curb' is the most formal and suggests actively holding back or controlling something that is considered undesirable, such as curbing pollution or curbing spending. In a sentence: 'The new safety rules restrict how workers can use the equipment, but it is the limited budget that truly constrains the company's ability to upgrade the facility.'

constrain ↗restrict ↗limit ↗curb ↗

Common collocations

Nouns

Adverbs

Phrases

  • constrained by circumstances
  • constrained to act
  • feel constrained to

Prepositions

Etymology

LatinOld FrenchEnglish

'Constrain' entered English through Old French 'constraindre', which came from Latin 'constringere' — a combination of 'com-' (together) and 'stringere' (to draw tight or bind). The original idea was to bind something tightly, which later developed into the more abstract sense of limiting or forcing.