Breaks down in tears (5)
(Other definitions for cries that I've seen before include "Decay in teeth" , "Weeps" , "Shouts; sheds tears" .)
'breaks down in tears' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sobs that I've seen before include "Weeps audibly" , "Weeps heavily (4)" , "Cries loudly" , "Weeps noisily" , "Is unhappy" .)