Easy-going couple of old men sent back food (9)
I believe the answer is:
adaptable
'easy-going' is the definition.
Both the answer and definition are adjectives. Perhaps there's a link between them I don't understand?
'couple of old men sent back food' is the wordplay.
I cannot really see how this works, but
'food' could be 'table' (table is a kind of food) and 'table' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for adaptable that I've seen before include "Able to be modified" , "Able to adjust to new conditions" , "Open to modification" , "Amenable to change, malleable" , "having different uses?" .)