The most common and most likely answer to this crossword clue is the 10 letter word SWEATSHIRT
I've seen this crossword clue in The Times
S
W
E
A
T
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H
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More clues leading to the result SWEATSHIRT
Buddy explains!
The straight part
We know that "garment" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case garment = sweatshirt.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 SWEATSHIRT mean?
SWEATSHIRT noun- A loose shirt, usually made of a knit fleece, for athletic wear and now often used as casual apparel.
- A shirt worn against the skin, usually under other clothing, to absorb sweat.