For an ownerless pet, it’s wrong (6)
I believe the answer is:
astray
'wrong' is the definition.
(going astray is going wrong)
'for an ownerless pet' is the wordplay.
I cannot quite see how this works, but
'an' could be 'a' and 'a' is found within the answer.
The remaining letters 'stray' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'it's' acts as a link.
Can you help me to learn more?
(Other definitions for astray that I've seen before include "wrong way" , "Off the correct track" , "Go . . . . . . - get lost" , "Up the garden path?" , "wide of the mark" .)