Recognise a key reputation (8)
I believe the answer is:
accredit
'recognise' is the definition.
(synonyms)
'a key reputation' is the wordplay.
'key' becomes 'c' (musical key).
'reputation' becomes 'credit' (I've seen this before).
'a'+'c'+'credit'='ACCREDIT'
(Other definitions for accredit that I've seen before include "Authorize" , "Trace CID and send them with credentials" , "Appoint" , "Show to be correct" , "Certify, approve" .)