Contradiction puts deal in trouble (6)
I believe the answer is:
denial
'contradiction' is the definition.
(I've seen this in another clue)
'deal in trouble' is the wordplay.
'trouble' indicates anagramming the letters.
'deal'+'in'='dealin'
'dealin' anagrammed gives 'DENIAL'.
'puts' acts as a link.
(Other definitions for denial that I've seen before include "Daniel (anag.)" , "Refusal to admit painful truths" , "Saying it isn't so" , "Refusal to acknowledge" , "Rejection or refusal" .)