Expression of approval (7)
I believe the answer is:
plaudit
'expression of approval' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for plaudit that I've seen before include "Commendation, acclamation" , "Praise, accolade" , "Praise bestowed" , "Acclaim" , "Salute" .)