(US, derogatory, chiefly in right-wing discourse) A judge or justice who makes rulings based on personal political views or considerations rather than on the law, or who issues rulings intended to have political effects.

plural of activist judge

(ice hockey) an ice hockey official who judges whether pucks enter the net and sits directly behind the goal, triggering a red light and siren when a goal is scored.

(US) A commissioned officer acting as a lawyer to advise a court martial on points of law or to act as prosecutor.

(simile) Completely sober.

(idiomatic) I do not believe what you said.

plural of lay judge

The chief judge of a car rally

A lay person who acts as (or is) a judge, or who assists a (professional) judge, in a court proceeding (especially in jurisdictions which do not use juries).

(sometimes derogatory) Created by judges or judicial decision; used especially of law applied or established by the judicial interpretation of statutes so as to extend or restrict their scope, as to meet new cases, to provide new or better remedies, etc.