Amusing person a diamond perhaps (4)
I believe the answer is:
card
I believe this is a double definition.
'amusing person' is the first definition.
(I've seen this before)
'a diamond perhaps' is the second definition.
(diamonds is a playing card suit)
(Other definitions for card that I've seen before include "Programme of events" , "amusing character" , "Eg, a heart or club" , "What may be used for greeting" , "Stiff paper; plastic money" .)