You can knock the stuffing out of them, chaps! (4)
I believe the answer is:
guys
'chaps' is the definition.
The definition and answer can be both man-made objects as well as being plural nouns.
Perhaps there's an association between them I don't understand?
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for guys that I've seen before include "Makes fun of < hospital" , "Men; ropes" , "Tent ropes; people" , "Men (with dolls?)" , "people generally" .)