Martini fruit (5)
I believe the answer is:
olive
'martini fruit' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for olive that I've seen before include "shades of green" , "Small green tree-fruit, nice in martini" , "Girl's name - colour" , "This branch is offered in peace gesture" , "Mediterranean fruit or greenish colour" .)