Philosopher's itchiest pants (8)

I believe the answer is:

ethicist

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

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

'itchiest pants' is the wordplay.
'pants' indicates an anagram (UK informal term for 'nonsense' or 'rubbish').
'itchiest' anagrammed gives 'ETHICIST'.

Can you help me to learn more?

(Other definitions for ethicist that I've seen before include "Moralist" , "Moral expert" .)

I've seen this clue in The Independent.

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