The most common and most likely answer to this crossword clue is the 12 letter word DISEMBOWELED
I've seen this crossword clue in The Guardian
D
I
S
E
M
B
O
W
E
L
E
D
Buddy explains!
The straight part
We know that "gutless" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case gutless = disemboweled.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 DISEMBOWELED mean?
DISEMBOWELED verb- To take or let out the bowels or interior parts of; to eviscerate.
- To take or draw from the body, as the web of a spider.