The most common and most likely answer to this crossword clue is the 7 letter word LADETTE
I've seen this crossword clue in The Daily Telegraph
L
A
D
E
T
T
E
More clues leading to the result LADETTE
- Guzzling girl due after draining coffee cups
- Short communication about a daughter being not the sort you want?
- Landlord briefly hugs poster girl who's feisty
- Hoyden departs for Yemeni capital in original outfit
- Unruly girl, out of time: liability inside bar, British
- Crude young woman reports what’s owed by the Spanish
- Shaking rear, character imbibing a shedload in the end — that’s her?
- Lager lass and editor upended into coffee
- A daughter in character wiping rear, offensive female
- Woman acting as boy, character shortly bagging a duke
Buddy explains!

The straight part
We know that "Vulgar woman" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case vulgar woman = ladette.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 LADETTE mean?
LADETTE noun- A young woman who behaves in a laddish manner, namely being boisterous and loud and drinking to excess.