The most common and most likely answer to this crossword clue is the 6 letter word WRETCH
I've seen this crossword clue in Financial Times
W
R
E
T
C
H
More clues leading to the result WRETCH
- Unfortunate person to throw up after whiskey
- Unfortunate to start being sick after first sign of winter
- We’re told gag, an unfortunate sort
- Good-for-nothing women heave
- Wife with cat, someone evoking pity?
- Poor chap’s attempt to be sick is heard
- Heartless war and the like, hard for unfortunate person
- Bastard making women vomit
- Bum soaked, last of water going in with both taps
- Scoundrel with gag
Buddy explains!

The straight part
We know that "Good-for-nothing" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case good-for-nothing = wretch.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 WRETCH mean?
WRETCH noun- An unhappy, unfortunate, or miserable person.
- An unpleasant, annoying, worthless, or despicable person.
- An exile.