Place for a boutonniere (5)
I believe the answer is:
lapel
'place for a boutonniere' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for lapel that I've seen before include "Continuation of a coat collar" , "Revere on a coat" , "Part of a folded back collar" , "Jacket fold" , "Feature of a jacket" .)