Watery discharge (5)
I believe the answer is:
rheum
'watery discharge' is the definition.
(watery discharge in the eyes)
This is the entire clue.
(Other definitions for rheum that I've seen before include "Catarrh" , "nasal discharge" , "Poetic tears" , "Rhubarb genus; a head cold" , "Tears of a cold" .)