Salivate (5)
I believe the answer is:
drool
'salivate' is the definition.
(drooling is a kind of salivating)
This is the entire clue.
(Other definitions for drool that I've seen before include "Show excitement" , "Spill saliva" , "Slaver - drivel" , "Let saliva run from the mouth" , "Dogs may" .)