Swear as 100p missing from wallet? (5)

I believe the answer is:

curse

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

'swear' is the definition.
(I know that swear can be written as curse)

'as 100p missing from wallet?' is the wordplay.
'as' becomes 'c' (I can't justify this - if you can you should believe this answer much more).
'c00p' becomes 'p'.
'missing from' indicates named letters should be taken away.
'wallet?' becomes 'purse' (I've seen this before).
'purse' with 'p' removed is 'urse'.
'c'+'urse'='CURSE'

Can you help me to learn more?

(Other definitions for curse that I've seen before include "Execrate" , "Imprecate" , "Invoke evil upon" , "Imprecation or oath" , "Execration" .)

I've seen this clue in The Guardian.

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.