It glistens on grass (3)
I believe the answer is:
dew
'it glistens on grass' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for dew that I've seen before include "Moisture on ground" , "Condensation during the night" , "Early-morning moisture" , "It forms on cool surfaces at night" , "Early freshness" .)