Sourpuss
I believe the answer is:
crab
'sourpuss' is the definition.
(both can mean a grumpy person)
This is the entire clue.
(Other definitions for crab that I've seen before include "Marine crustacean (seen on 1 across?)" , "Seafood (that can be caught by a rower?)" , "move obliquely" , "winch" , "Clawed crustacean" .)