Cut nothing back when getting old (4)
I believe the answer is:
loin
'cut' is the definition.
(cut of meat)
'nothing back when getting old' is the wordplay.
I cannot really understand how this works, but
'nothing' could be 'o' (O resembles 0) and 'o' is found in the answer.
The remaining letters 'lin' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for loin that I've seen before include "Either side of the backbone between the hip bone and ribs" , "Beef cut" , "Cut of meat from the lower back and sides" , "Part of the back - cut of meat" , "Cut of meat from between the ribs and rump" .)