Overeat (5)
I believe the answer is:
gorge
'overeat' is the definition.
(I know that overeat can be written as gorge)
This is the entire clue.
(Other definitions for gorge that I've seen before include "Canyon or ravine" , "Stuff oneself (with) - Cheddar, for example" , "Deep valley" , "Overindulge" , "Overeat in the deep ravine" .)