Swelling, be very angry (4)
I believe the answer is:
boil
This clue is a double definition.
'swelling' is the first definition.
(thesaurus)
'be very angry' is the second definition.
(Other definitions for boil that I've seen before include "Cook in hot water" , "Skin swelling; cause to evaporate" , "Bubble up - inflamed swelling" , "let off steam" , "become inflamed" .)