The mutineers thought him a bit of a blighter (5)
I believe the answer is:
bligh
But I can't explain it at all! Could you help me understand?
(Other definitions for bligh that I've seen before include "HMS Bounty's captain" , "HMS Bounty captain" , "old captain dismissed" , "CA [CHILDRENS ADVENTURE] captain" , "The mutinous Bounty's captain" .)