Intelligence and excellence about one restaurant worker (10)

I believe the answer is:

headwaiter

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

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

'excellence about one restaurant worker' is the wordplay.
'excellence about' becomes 'head' (I can't explain this - if you can you should give a lot more credence to this answer).
'one restaurant worker' becomes 'waiter' (I've seen this in another clue).
'head'+'waiter'='HEADWAITER'

'and' is the link.

Can you help me to learn more?

I've seen this clue in The Times.

Want a hint initially instead of a full solution? Install my app