English Reference
verb

cooperate

v.
US /ˈkwɑpɝˌeɪt/ UK /kəʊˈɒpəɹˌeɪt/ co·op·er·ate UK spelling cooperated, cooperates, cooperating

  1. 01 B1 Intermediate

    to work with other people to reach a common goal or finish a task.

    to act or work jointly with others for a mutual benefit or common purpose.

    Simple

    The two companies decided to cooperate on a new project to build electric cars.

    In context

    Local authorities and environmental groups must cooperate closely if they hope to restore the river's ecosystem within the next decade.

    Usage

    Usually followed by the preposition 'with' for people and 'on' for tasks.

  2. 02 B2 Upper Intermediate

    to do what someone asks you to do, especially an official or a person in charge.

    to comply with the requests or instructions of others, particularly those in authority.

    Simple

    The witness agreed to cooperate with the police and told them everything she saw.

    In context

    Despite initial hesitation, the suspect eventually chose to cooperate fully with the investigation in exchange for a reduced sentence.

    Usage

    Often used in the context of police investigations or following rules.

  3. 03 C1 Advanced Literary

    when things work well together to produce a good result.

    to function or operate in harmony; used of inanimate objects or abstract forces that align to produce a specific outcome.

    Simple

    The weather did not cooperate, and our outdoor party was ruined by rain.

    In context

    For the experiment to succeed, every variable must cooperate perfectly, as even a minor fluctuation in temperature could invalidate the results.

  4. 04 C2 Proficiency TechnicalAmerican English Law

    to persuade someone to help the police or a court, usually by offering them a deal.

    to obtain the formal assistance of a potential witness, often by offering legal incentives.

    Simple

    The prosecutor spent months trying to cooperate the driver of the getaway car.

    In context

    Federal agents successfully cooperated the lead accountant, whose testimony provided the evidence needed to dismantle the entire criminal enterprise.

    Usage

    In this specific legal sense, the verb is used transitively.

Species that live this way form colonies containing overlapping generations, cooperate in raising young and divide reproductive responsibilities.

ScienceDaily· 15 Aug 2026

People like that would have to be “out of the inner circle” before Reform UK would hold talks with Restore Britain about cooperating, he said.

The Guardian· 10 Aug 2026

Originated 1595–1605 from Late Latin cooperātus, perfect passive participle of cooperor (“to work with”), see -ate (verb-forming suffix) for more. Equivalent to co- + operate. Displaced native Old English efnwyrċan.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin la-lat cooperātus
Level C1 · Advanced
Frequency Frequent
Updated