Stupidity of answer getting disdainful remark by head (9)

I believe the answer is:

apishness

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'stupidity' is the definition.
Both the definition and answer are singular nouns.
Maybe they are linked in a way I don't understand?

'answer getting disdainful remark by head' is the wordplay.
'answer' becomes 'a' (abbreviation eg in Q and A).
'getting' says to put letters next to each other.
'disdainful remark' becomes 'pish' (I've seen this in another clue).
'by head' becomes 'ness' (type of geographical point. I am not sure about the 'by' bit.).
'a'+'pish'+'ness'='APISHNESS'

'of' acts as a link.

Can you help me to learn more?

(Another definition for apishness that I've seen is " Condition of primate".)

I've seen this clue in The Times.

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