Charm so you find yourself unable to fire? (6)

I believe the answer is:

disarm

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

'charm' is the definition.
(I've seen this in another clue)

I don't understand how the rest of the clue works.

(Other definitions for disarm that I've seen before include "Deprive of weapons or win over" , "Relieve of weapons" , "Take weapons from or make less hostile" , "to allay hostility" , "Do away with weaponry" .)

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.