Finish without justification for crime (7)
I believe the answer is:
treason
'crime' is the definition.
(treason is a kind of crime)
'finish without justification' is the wordplay.
'finish' says to take the final letters.
'justification' becomes 'reason' (I've seen this before).
The last letter of 'without' is 't'.
't'+'reason'='TREASON'
'for' acts as a link.
(Other definitions for treason that I've seen before include "Crime agains one's country" , "One's art? (anag)" , "One rats (anag)" , "Lese-majesty" , "Criminal attempt to overthrow a government" .)