Relative swelling on giving up carbohydrate (5)
I believe the answer is:
uncle
'relative' is the definition.
(uncle is a kind of relative)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for uncle that I've seen before include "one who's taken the pledge" , "He's related" , "Slang name for pawnbroker" , "older relative" , "One receiving pawn" .)