After money, they're fat cats (4)

I believe the answer is:

bags

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

'cats' is the definition.
The definition and answer can be both acts as well as being plural nouns.
Perhaps you can see a link between them that I don't see?

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for bags that I've seen before include "Flexible container" , "Flexible containers, of paper say" , "Criticises" , "I claim" , "Takes unilaterally" .)

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.