Part of the large intestine (5)
I believe the answer is:
colon
'part of the large intestine' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for colon that I've seen before include "that may cut sentence" , "Part of body; some punctuation" , "Punctuation mark; gut" , "Panamanian port" , "unit of foreign currency" .)