Sign of sorrow or rage (4)
I believe the answer is:
tear
I believe this clue is a double definition.
'sign of sorrow' is the first definition.
(I've seen this before)
'rage' is the second definition.
(thesaurus)
'or' is the link.
(Other definitions for tear that I've seen before include "Lachrymal fluid" , "Rend; travel in haste" , "wrench" , "Secretion of the lacrymal glands" , "Rip; salty drop" .)