A large provision of weapons is causing panic (8)

I believe the answer is:

alarming

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

'weapons is causing panic' is the definition.
I can't tell whether this definition defines the answer.

'a large provision' is the wordplay.
'large' becomes 'L' (eg in clothes sizes).
'provision' becomes 'arming' (I can't justify this - if you can you should believe this answer much more).
'a'+'l'+'arming'='ALARMING'

'of' is the link.

Can you help me to learn more?

(Other definitions for alarming that I've seen before include "causing fright" , "Worrying or disturbing" , "Dangerous" , "Marginal (anag)" , "Scary, frightening" .)

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.