The most common and most likely answer to this crossword clue is the 4 letter word GROT
I've seen this crossword clue in The Times
G
R
O
T
Buddy explains!
The straight part
We know that "G-garbage" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case g-garbage = grot.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 GROT mean?
GROT noun- A grotto.
- Any unpleasant substance or material.
- A miserable person.