Authorise riotous pop rave (7)
I believe the answer is:
approve
'authorise' is the definition.
(I know that approve is a type of authorise)
'riotous pop rave' is the wordplay.
'riotous' is an anagram indicator.
'pop'+'rave'='poprave'
'poprave' is an anagram of 'APPROVE'.
(Other definitions for approve that I've seen before include "OK" , "Consider right" , "Sanction, authorise" , "Give the go-ahead" , "Say yes to" .)