The most common and most likely answer to this crossword clue is the 11 letter word VINAIGRETTE
I've seen this crossword clue in The Times
V
I
N
A
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G
R
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E
More clues leading to the result VINAIGRETTE
- Dressing in very fashionable plumed headdress
- Vintage rite involved sharp dressing
- What's used to dress model given attire
- Invite detective to move hat forward slightly, as dressing
- Vogue’s first with trendy feather dressing
- Dressing, being given attire in new fashion
- Integrative reforms that will be put on the table in France
Buddy explains!

The straight part
We know that "What's used to dress" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case what's used to dress = vinaigrette.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 VINAIGRETTE mean?
VINAIGRETTE noun- A sauce, made of an acidic liquid such as vinegar or lemon juice; oil; and other ingredients, used as a salad dressing, or as a marinade for cold meats.
- A small perforated box for holding aromatic vinegar contained in a sponge, or a smelling bottle for smelling salts; called also vinegarette.
- A small, two-wheeled vehicle, like a Bath chair, to be drawn or pushed by a boy or man.
- A sort of Russian salad, originally using French salad dressing.