Martini garnish (5)
I believe the answer is:
olive
'martini garnish' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for olive that I've seen before include "Type of green" , "Evergreen Mediterranean tree" , "Its branch is a peace emblem" , "shades of green" , "Fruit; Popeye's girlfriend" .)