Oscar wearing dog/cat combo as part of fancy dress outfit (4,4)
I believe the answer is:
tail coat
'fancy dress outfit' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'oscar wearing dogcat combo as part' is the wordplay.
I cannot really understand how this works, but
'oscar' could be 'o' (phonetic alphabet: alpha, bravo, charlie etc.) and 'o' is found in the answer.
'part' could be 'tail' (tail is a kind of part) and 'tail' is found within the answer.
The remaining letters 'cat' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'of' acts as a link.
Can you help me to learn more?
(Other definitions for tail coat that I've seen before include "Man's formal jacket" , "item of clothing" , "Male formal dress" , "Man's formal wear" .)