The most common and most likely answer to this crossword clue is the 5 letter word KHADI
I've seen this crossword clue in Financial Times
K
H
A
D
I
More clues leading to the result KHADI
Buddy explains!
The straight part
We know that "exotic material for garment" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case exotic material for garment = khadi.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.
Crossword Answer definitions
KHADI noun- A coarse homespun cotton cloth from India.