An inclination to be crooked (4)
I believe the answer is:
bent
I believe this is a double definition.
'an inclination' is the first definition.
(I know that bent is a type of inclination)
'be crooked?' is the second definition.
(both can mean corrupt)
'to' is the link.
(Other definitions for bent that I've seen before include "Not straight" , "Dishonest, corrupt" , "Angled; corrupt" , "Misshapen" , "Natural talent" .)