noun
collusion; conspiracy; secret agreement
Refers to two or more parties secretly cooperating for a dishonest or improper purpose, often in business, politics, or competitive settings.
その企業は入札で馴れ合いをしていたと疑われている。
The company is suspected of collusion in the bidding.
審査員と出場者の間
There seems to have been collusion between the judges and the contestants.
noun
illicit sexual relationship; liaison; common-law marriage
Older or literary term for a secret romantic or sexual relationship, sometimes implying an improper or informal union. Modern usage is rare; more common terms include 不倫 or 内縁関係.
昔の小説には、男女の馴れ合いがよく描かれている。
Old novels often depict illicit liaisons between men and women.
Derived from the verb 馴れ合う (to become familiar with each other and act in concert), from 馴れる (to become tame/familiar) + 合う (mutual). The noun form 馴れ合い originally meant 'becoming familiar with each other' and developed the negative connotation of improper collusion or secret intimacy.