The most common and most likely answer to this crossword clue is the 8 letter word COSTUMES
C
O
S
T
U
M
E
S
Buddy explains!

The straight part
We know that "Dresses" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case dresses = costumes.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 COSTUMES mean?
COSTUMES noun- A style of dress, including garments, accessories and hairstyle, especially as characteristic of a particular country, period or people.
- An outfit or a disguise worn as fancy dress etc.
- A set of clothes appropriate for a particular occasion or season.
- To dress or adorn with a costume or appropriate garb.