Don't eat in a quick way (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
fast
This clue is a double definition.
'don't eat' is the first definition.
(fasting is not eating)
'in a quick way' is the second definition.
(I know this)
(Other definitions for fast that I've seen before include "Maybe bound to spot" , "Don't scoff" , "requiring only brief exposure" , "not lento" , "fare-dodging" .)