The most common and most likely answer to this crossword clue is the 7 letter word RAUNCHY
I've seen this crossword clue in The Daily Telegraph
R
A
U
N
C
H
Y
More clues leading to the result RAUNCHY
Buddy explains!

The straight part
We know that "Coarse" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case coarse = raunchy.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 RAUNCHY mean?
RAUNCHY adjective- Smutty; indecent.
- Lecherous.
- Sexually seductive.
- Very low-class; inferior; inadequate.
- With dishonorable, base and vulgar expression.