They dress in blue - not silver (7)

I believe the answer is:

coppers

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

'they' is the definition.
Both the definition and answer are plural nouns.
Perhaps they are linked in a way I don't understand?

I don't understand the rest of the clue.

Can you help me to learn more?

(Other definitions for coppers that I've seen before include "Officers" , "The boys in blue (slang)" , "loose change?" , "Pence" , "Constabulary" .)

I've seen this clue in The Globe and Mail and The Irish News.

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.