Stop boss being an idiot (9)

I believe the answer is:

blockhead

'an idiot' is the definition.
(I know that blockhead is a type of idiot)

'stop boss' is the wordplay.
'stop' becomes 'block' (synonyms).
'boss' becomes 'head' (synonyms).
'block'+'head'='BLOCKHEAD'

'being' acts as a link.

(Other definitions for blockhead that I've seen before include "Dolt" , "Stupid person" .)

I've seen this clue in The Independent and The Sun.

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