The most common and most likely answer to this crossword clue is the 7 letter word BODICES
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More clues leading to the result BODICES
Buddy explains!

The straight part
We know that "undergarments" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case undergarments = bodices.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 BODICES mean?
BODICES noun- A sleeveless shirt for women, sometimes provided with detachable sleeves.
- Blouse; any shirt for women, particularly the upper part of a two-piece dress or European folk costume.
- The upper portion of a women's one-piece dress, equivalent to a shirt.
- Underbodice: an undershirt for women, particularly a corset or other undershirt stiffened with whalebone.