The most common and most likely answer to this crossword clue is the 7 letter word KIRTLES
I've seen this crossword clue in The Guardian
K
I
R
T
L
E
S
Buddy explains!
The straight part
We know that "old gowns" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case old gowns = kirtles.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 KIRTLES mean?
KIRTLES noun- A knee-length tunic.
- A short jacket.
- A woman's gown; a woman's outer petticoat or skirt.
- To clothe or cover with, or as if with, a kirtle; to hitch up (a long garment) to the length of a kirtle.
- Clothed or covered with, or as if with, a kirtle.