Long look and tears when upset (5)
I believe the answer is:
stare
'long look' is the definition.
(I've seen this in another clue)
'tears when upset' is the wordplay.
'when upset' is an anagram indicator.
'tears' is an anagram of 'STARE'.
'and' is the link.
(Other definitions for stare that I've seen before include "Look hard" , "Gawp" , "Look with fixed eyes" , "Gaze fixedly" , "Rates (anag.)" .)