Bent course, one's twisted at first (9)
I believe the answer is:
dishonest
'bent' is the definition.
(bent can mean corrupt)
'course one's twisted at first' is the wordplay.
'course' becomes 'dish' (dish can mean a course of a meal).
'at first' suggests taking the first letters.
The first letter of 'twisted' is 't'.
'dish'+'ones'+'t'='DISHONEST'
(Other definitions for dishonest that I've seen before include "Corrupt" , "shifty" , "cheating" , "Mendacious like hedonists" , "Fraudulent" .)