Big toe swelling (6)
I believe the answer is:
bunion
'big toe swelling' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for bunion that I've seen before include "Swelling on the foot" , "Foot fault" , "Swelling at base of toe with thickened skin" , "Painful swelling of the big toe joint" , "Painful swelling at base of big toe" .)