Aggression from cat holding glare (9)

I believe the answer is:

pushiness

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

'aggression' is the definition.
(thesaurus)

'cat holding glare' is the wordplay.
'cat' becomes 'puss' (puss is a kind of cat).
'holding' means one lot of letters goes inside another.
'glare' becomes 'shine' (I can't justify this - if you can you should believe this answer much more).
'puss' placed around 'shine' is 'PUSHINESS'.

'from' acts as a link.

Can you help me to learn more?

(Other definitions for pushiness that I've seen before include "Self-assertion; ambition" , "Ambitious quality" .)

I've seen this clue in The Telegraph.

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.