Free trader even up, perhaps (12)
I believe the answer is:
peradventure
'perhaps' is the definition.
(synonyms)
'free trader even up' is the wordplay.
'free' indicates anagramming the letters.
'trader'+'even'+'up'='traderevenup'
'traderevenup' with letters rearranged gives 'PERADVENTURE'.
(Other definitions for peradventure that I've seen before include "Maybe" , "by chance" , "Possibly (archaic)" , "perhaps" .)