Final letters from income tax cop? No fair! (4)
I believe the answer is:
expo
'fair' is the definition.
(an expo is a type of large exhibition)
'final letters from income tax cop? no' is the wordplay.
I cannot quite see how this works, but
'from' could be 'o' (I've seen this in other clues) and 'o' is found within the answer.
The remaining letters 'exp' 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).
Can you help me to learn more?
(Other definitions for expo that I've seen before include "Large international exhibition" , "public display" , "Large international fair" , "Public exhibition" , "Show" .)