Tool for tidying up back (7)

I believe the answer is:

sweeper

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

'back' is the definition.
(football term)

I cannot understand how the remainder of the clue works.

(Other definitions for sweeper that I've seen before include "Last football defender before the goalkeeper" , "'Football defender, carries a brush (7)'" , "One using broom" , "Soccer player" , "Soccer defender" .)

I've seen this clue in The Telegraph.

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.