Unusual trade-in worked out (7)
I believe the answer is:
trained
'worked out' is the definition.
(training is a kind of working out)
'unusual trade-in' is the wordplay.
'unusual' indicates anagramming the letters.
'trade'+'in'='tradein'
'tradein' with letters rearranged gives 'TRAINED'.
(Other definitions for trained that I've seen before include "Schooled" , "Coached" , "Taught; exercised" , "Did exercises" , "Prepared for a task or career" .)