Swell up (5)
'swell up' is the definition.
(I know that swell up can be written as intumesce)
This is the entire clue.
'swell up' is the definition.
(I know that bloat is a kind of swell up)
This is all the clue.
(Other definitions for bloat that I've seen before include "Thus treat some fish" , "Fill up with gas" , "Puff out" , "Make swollen" , "Cause to swell" .)