Is quite cutting while they're eating (6)
I believe the answer is:
biting
'eating' is the definition.
Although both the answer and definition are present participle verbs, I can't understand how one could define the other.
'is quite cutting while' is the wordplay.
I cannot really see how this works, but
'while' could be 'bit' (both can mean an amount of time) and 'bit' is present in the answer.
This explanation may well be incorrect...
'they're' is the link.
Can you help me to learn more?
(Other definitions for biting that I've seen before include "Mordant" , "Painful or stinging" , "Acerbic" , "Cold - tart" , "Keen" .)