Corpulent boss, not very clever (7)

I believe the answer is:

fathead

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'not very clever' is the definition.
I can't judge whether this defines the answer.

'corpulent boss' is the wordplay.
'corpulent' becomes 'fat' (similar in meaning).
'boss' becomes 'head' (synonyms).
'fat'+'head'='FATHEAD'

Can you help me to learn more?

(Other definitions for fathead that I've seen before include "Fool" , "Dimwit" , "Slang idiot with enlarged cranium?" , "Charlie" , "Stupid person" .)

I've seen this clue in the Evening Standard.

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