The most common and most likely answer to this crossword clue is the 6 letter word DENIMS
I've seen this crossword clue in The Times
D
E
N
I
M
S
More clues leading to the result DENIMS
Buddy explains!

The straight part
We know that "Perhaps designer garments" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case perhaps designer garments = denims.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 DENIMS mean?
DENIMS noun- Jeans made of denim.