Cries convulsively (4)
I believe the answer is:
sobs
'cries convulsively' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sobs that I've seen before include "Weeps noisily" , "Given evidence of distress" , "Weeps heavily for boss" , "Cries noisily" , "showing distress" .)