Cranks may be motivated by such an odd character (9)
I believe the answer is:
eccentric
'character' is the definition.
(synonyms)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for eccentric that I've seen before include "Off-the-wall" , "Bizarre" , "Offbeat" , "Unconventional in appearance or behaviour" , "character" .)