Rushes at signs of sadness (5)
I believe the answer is:
tears
This clue is a double definition.
'rushes' is the first definition.
(tearing is a kind of rushing)
'signs of sadness' is the second definition.
(I've seen this in another clue)
'at' acts as a link.
(Other definitions for tears that I've seen before include "Lacerations (before bedtime?)" , "Shed them and cry" , "Rends" , "Water in eyes" , "Show of emotion" .)