Abstains from food (5)
I believe the answer is:
fasts
'abstains from food' is the definition.
('fast' can be a synonym of 'abstain from food')
This is all the clue.
(Other definitions for fasts that I've seen before include "Times of abstinence" , "Avoids food" , "Abstains from food" , "Goes without food" , "Goes hungry" .)