The most common and most likely answer to this crossword clue is the 6 letter word CHOMPS
C
H
O
M
P
S
Buddy explains!
The straight part
We know that "Munches noisily" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case munches noisily = chomps.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 CHOMPS mean?
CHOMPS noun- The act of chomping (see below)
- To bite or chew loudly or heavily.
- (Perl) To remove the final character from (a text string) if it is a newline (or, less commonly, some other programmer-specified character).