Threesome left out rubbish (5)
I believe the answer is:
tripe
'rubbish' is the definition.
(both can mean nonsense)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for tripe that I've seen before include "Rubbish (edible, maybe)" , "Junk; food" , "Garbage" , "Something to eat" , "Edible entrails" .)