Mix around (4)
I believe the answer is:
stir
'mix around' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for stir that I've seen before include "Whisk or make a move" , "Commotion; wake" , "Prison (slang) - disturbance" , "Detention centre" , "Cause to move in slangy prison" .)