Crossword Genius

Move jug (4)

Ross

I believe the answer is:

stir

This clue is a double definition.

'move' is the first definition.
(stir can mean to make a movement)

'jug' is the second definition.
(both are slang for prison)

(Other definitions for stir that I've seen before include "jail" , "move very slightly, or agitate" , "Start to move" , "Whisk, agitate" , "in which you'll find people with convictions" .)

I've seen this clue in The Times and The Guardian.
Want a hint initially instead of a full solution? Install my app