Mere agent prepared contract (9)
I believe the answer is:
agreement
'contract' is the definition.
(thesaurus)
'mere agent prepared' is the wordplay.
'prepared' indicates an anagram.
'mere'+'agent'='mereagent'
'mereagent' anagrammed gives 'AGREEMENT'.
(Other definitions for agreement that I've seen before include "Unlikely result" , "Conformity" , "Concord, harmony" , "Harmony or treaty" , "concert" .)