English Reference
noun

collusion

n.
US /kəˈɫuʒən/ UK /kəlˈuːʒən/ col·lu·sion UK spelling collusions

  1. 01 C1 Advanced FormalTechnical Law

    a secret plan between people or companies to do something dishonest or illegal.

    a secret agreement or cooperation for a fraudulent or illegal purpose; conspiracy.

    Simple

    The two companies were accused of collusion to keep prices high for customers.

    In context

    The investigation uncovered evidence of collusion between the regulators and the very companies they were supposed to be monitoring.

    Usage

    Often used with the preposition 'between' or 'with'.

    Teacher's tip

    Learners should note that collusion always implies a level of secrecy and dishonesty; it is never used for positive cooperation.

  2. 02 C1 Advanced FormalAcademic

    when groups that should be competing secretly work together to gain an unfair advantage.

    a private arrangement between groups that maintain a public appearance of competition or non-cooperation.

    Simple

    The two political parties were in collusion to prevent a third candidate from winning.

    In context

    Economists warned that the lack of price variation suggested collusion among the major airlines rather than a healthy competitive market.

    Usage

    Uncountable when referring to the abstract concept; countable when referring to specific instances.

    Teacher's tip

    This sense is common in business and political journalism to describe 'rigged' systems.

Following the UAE's decision, Iran's armed forces warned neighbouring Gulf countries against providing support to the US military, saying any assistance given to US forces would be considered collusion.

BBC News· 20 Aug 2026

This did not entirely bury the question of collusion between teams nor the fact that those playing later had a competitive advantage in knowing what result they needed to progress.

The Guardian· 22 Jul 2026

Dated from the 14th century C.E. as Middle English collusioun, collusion; from Old French collusion, from Latin collusio (“act of colluding”).

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

This entry
Origin Latin collusio
Level C1 · Advanced
Frequency Frequent
Updated