Laugh about women’s gossip (7)
I believe the answer is:
'gossip' is the definition.
(thesaurus)
'laugh about women's' is the wordplay.
'laugh' becomes 'titter' (titter is a kind of laugh).
'about' means one lot of letters goes inside another.
'women' becomes 'w' (standard abbreviation).
'titter' placed around 'w' is 'TWITTER'.
(Other definitions for twitter that I've seen before include "Sound like small birds" , "limited communications network" , "Chirping (could be electronic!)" , "Electronic social network" , "flutter" .)