Kiss lightly (4)
I believe the answer is:
peck
'kiss lightly' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for peck that I've seen before include "Strike with beak" , "Bite lightly; a dry measure" , "Kiss; old dry measure" , "One quarter of a bushel" , "Eat just a bit" .)