Conqueror written of as 'Just' (7)

I believe the answer is:

william

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

'conqueror' is the definition.
Both the definition and answer are singular nouns.
Perhaps there's a link between them I don't understand?

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for william that I've seen before include "I am a weakish speller (anag) -- author" , "Shakespeare or Pitt, say" , "Prince Harry's brother" , "Bill" , "- - Wordsworth" .)

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.