Colleague removing last of garbage from narrow street (4)
I believe the answer is:
ally
'colleague' is the definition.
(ally can mean a colleague or associate)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for ally that I've seen before include "A friendly and reliable country" , "One co-operating with another" , "Join by marriage, treaty etc" , "Join forces with" , "Confederate; supporter" .)