The most common and most likely answer to this crossword clue is the 9 letter word DRUNKARDS
I've seen this crossword clue in The Daily Telegraph
D
R
U
N
K
A
R
D
S
More clues leading to the result DRUNKARDS
Buddy explains!
The straight part
We know that "Draughtsmen who’ve been overindulgent" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case draughtsmen who’ve been overindulgent = drunkards.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 DRUNKARDS mean?
DRUNKARDS noun- (somewhat derogatory) A person who is habitually drunk.