The most common and most likely answer to this crossword clue is the 6 letter word LOAFER
L
O
A
F
E
R
Buddy explains!
The straight part
We know that "one does nothing" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one does nothing = loafer.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 LOAFER mean?
LOAFER noun- An idle person.
- A shoe with no laces, resembling a moccasin.
- A wolf, especially a grey or timber wolf.