Not to be confused with a stray? (4)
I believe the answer is:
waif
'stray?' is the definition.
(I've seen this in another clue)
'not to be confused with a' is the wordplay.
I cannot really see how this works, but
'with' could be 'w' (short for with) and 'w' is located in the answer.
'a' is present in the answer.
The remaining letters 'if' 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 waif that I've seen before include "poor child" , "neglected issue" , "Orphan" , "Be incongruous" , "Neglected, homeless child" .)