Two with spirit eat heartily (3,2)
I believe the answer is:
dig in
'eat heartily' is the definition.
(synonyms)
'two with spirit' is the wordplay.
I cannot quite see how this works, but
'spirit' could be 'gin' (alcoholic spirit) and 'gin' is found within the answer.
The remaining letters 'di' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for dig in that I've seen before include "Begin eating (informal)" , "prepare trench" , "protect himself" , "Start eating (informal)" , "Begin eating heartily" .)