Say what tireless seamstresses do for rotter? (2-3-2)
I believe the answer is:
so-and-so
'rotter?' is the definition.
(I know that bum can be written as so-and-so)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for so-and-so that I've seen before include "This or that person or thing" , "No sodas for this unpleasant person" , "Disliked person" , "Difficult person - nobody in particular" , "Unpleasant person - whose name has been forgotten!" .)