Snap top off with laugh (5)
I believe the answer is:
photo
'snap' is the definition.
(I've seen this before)
'top off with laugh' is the wordplay.
'off' indicates an anagram.
'with' is an insertion indicator.
'laugh' becomes 'ho' (representation of a laughing sound).
'top' is an anagram of 'pto'.
'pto' enclosing 'ho' is 'PHOTO'.
(Other definitions for photo that I've seen before include "Snap (abbrev.)" , "Snap, exposure, in short" , "Camera picture" , "This race finish is very close" , "Still" .)