Saline sign of sadness (4)
I believe the answer is:
tear
'saline sign of sadness' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tear that I've seen before include "'A rip, binge or drop of saline solution (4)'" , "wrench" , "Rip or lacerate" , "Droplet from the eye" , "Rip - eye moisture" .)