Have a good cry (4)
I believe the answer is:
bawl
'have a good cry' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for bawl that I've seen before include "Cry loudly" , "Supporter of Charles I" , "Loudly greet" , "What baby does" , "Shout loudly" .)