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

plural of floating island

As a consequence of one's own skill, qualification or status, rather than that of another.

by itself; with respect to its intrinsic or inherent nature without consideration of extraneous factors; per se, intrinsically, inherently

(idiomatic) To announce one's candidacy in a contest