(idiomatic) Something concealed; a hidden danger.

A criminal accomplice. / (informal, humorous) A close associate.

Something extremely rare or unlikely.

plural of dog in the manger

A substitute; a replacement.

To substitute for; to replace; (theater) to serve as an understudy. / To make one of a party in a bet or other speculation. / To take a side in a dispute.

Synonym of inside joke (“a joke that is understood or meant to be understood only by certain people who are aware of the details”)

Alternative form of look what the cat's dragged in

(idiomatic) Used as an ironic acknowledgement of someone's arrival, especially to imply that they are unwelcome or disagreeable in some way.

plural of case in point