noun
collusive relationship; extremely close (often improper) ties
Refers to an overly cozy, often improper relationship between entities that should remain independent, such as government and industry, or regulators and the regulated. Carries a strong negative connotation of collusion or mutual back-scratching.
政治家と企業の癒着関係が問題になっている。
The collusive relationship between politicians and corporations has become a problem.
癒着関係を断ち切るための改革が必要だ。
Reforms are needed to sever these cozy ties.
Compound of 癒着 (ゆちゃく, 'adhesion; collusion') and 関係 (かんけい, 'relationship'). The figurative sense of improper closeness derives from the medical sense of tissues adhering abnormally.