Skinny guy has a lot of leftovers for the dog (3,2,5)
I believe the answer is:
bag of bones
'leftovers for the dog' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.
'skinny guy has a lot of' is the wordplay.
I cannot really see how this works, but
'a' could be 'one' and 'one' is present in the answer.
'of' could be 'o' and 'o' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for bag of bones that I've seen before include "Extremely thin person" , "case for doctor?" .)