The most common and most likely answer to this crossword clue is the 7 letter word ENTRAIL
I've seen this crossword clue in The Daily Telegraph
E
N
T
R
A
I
L
Buddy explains!

The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ENTRAIL mean?
ENTRAIL verb- To interweave or bind.
- To outline in black.
- Entanglement; fold.