Most powerful men on board, but not at court (6)

I believe the answer is:

queens

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

'most powerful men' is the definition.
'queens' can be an answer for 'men' (queen is a kind of man). I am unsure of the 'most powerful' bit.

I can't explain the rest of the clue.

Can you help me to learn more?

(Other definitions for queens that I've seen before include "powerful men on board" , "Brooklyn's neighbour" , "Borough of NYC for the royals" , "Most powerful pieces in chess games" , "Borough of New York City for monarchs" .)

I've seen this clue in The Guardian.

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