Steal a small amount (5)
I believe the answer is:
pinch
I believe this clue is a double definition.
'steal' is the first definition.
(pinch can mean to steal)
'a small amount' is the second definition.
(I've seen this in another clue)
(Other definitions for pinch that I've seen before include "Squeeze between the fingers" , "Steal - a little salt, for example" , "Steal; small quantity" , "Steal (informal); squeeze" , "Grip sharply; steal" .)