Fool Oscar but not Wilde? (4-3)

I believe the answer is:

half-wit

I'm a little stuck... Click here to teach me more about this clue!

'fool' is the definition.
(I've seen this before)

I can't explain the rest of the clue.

(Other definitions for half-wit that I've seen before include "Fool" , "Idiot" , "Hit flaw (anag.)" , "Nincompoop" , "One only 50% all there?" .)

I've seen this clue in The Sun.

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