Sire, he's upset: she inherits the prize (7)

I believe the answer is:

heiress

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

'sire he's upset she inherits the prize' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.

'sire he's upset' is the wordplay.
'upset' is an anagram indicator.
'sire'+'hes'='sirehes'
'sirehes' anagrammed gives 'HEIRESS'.

Can you help me to learn more?

(Other definitions for heiress that I've seen before include "one who's succeeded" , "One due to inherit" , "One coming into wealth" , "Woman with good prospects" , "Woman who will inherit great wealth" .)

I've seen this clue in The Independent.

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.