Struggling for idea, as previously mentioned (9)
I believe the answer is:
aforesaid
'previously mentioned' is the definition.
(I've seen this before)
'struggling for idea as' is the wordplay.
'struggling' indicates an anagram (I've seen this in other clues).
'for'+'idea'+'as'='forideaas'
'forideaas' is an anagram of 'AFORESAID'.
(Other definitions for aforesaid that I've seen before include "earlier" , "The one previously mentioned" , "previously referred to" , "Above-mentioned" .)