In cheerful mood, trimming carpet (7)
I believe the answer is:
upbraid
'carpet' is the definition.
(thesaurus)
'in cheerful mood trimming' is the wordplay.
'in cheerful mood' becomes 'up'.
'trimming' becomes 'braid' (braid is a kind of trimming).
'up'+'braid'='UPBRAID'
(Other definitions for upbraid that I've seen before include "Reproach strongly over arid pub" , "Rebuke, scold severely" , "Find fault with" , "Reprove" , "Angrily reproach" .)