Taking regular breaks, group stop to plunder (3)
I believe the answer is:
gut
'plunder' is the definition.
(I've seen this in another clue)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for gut that I've seen before include "Remove innards from" , "Stomach, belly" , "Remove the insides, of a fish say" , "Part of the alimentary canal" , "Rip out (a place's) interior" .)