Toss (a coin) (4)
I believe the answer is:
flip
'toss a coin' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for flip that I've seen before include "Get angry" , "ale mixed with spirits ..." , "Lose one's cool - reverse side" , "See red" , "Turn quickly over; sort of chart" .)