A suitable outburst (3)
I believe the answer is:
fit
This clue is a double definition.
'a suitable' is the first definition.
(I've seen this in another clue)
'outburst' is the second definition.
(synonyms)
(Other definitions for fit that I've seen before include "In good physical condition, healthy" , "Match" , "In good shape; sudden attack" , "Be the right size or shape" , "Of a suitable standard" .)