Another guess but after looking around some more, and finding clothing without flounces. And realizing that another unifying feature of these clothes is asymmetry.

So my guess is
abito asimmetrico o
(con cuciture) asimmetriche

see for example
Inhibitor | Arts Council Collection
https://www.artscouncilcollection.org.uk › artwork › in...
... videos, film and sound, with an emphasis on privileging the handmade, the awkward and the asymmetrical, an aesthetic the artist describes as 'shonky'.

https://www.spacetoshow.com › products › gabriella-on...
Gabriella One Shoulder Abstract Print Shonky Dress
It's one shoulder neckline gives it a flattering, soft asymmetry with fluid lines gently following the body. Elasticated at the waist to define the shape, with ...

here is a shonky dress without flounces:
https://www.shopstyle.com/g/women/nanushka/sloan-shonky-dres...

a hint here:
https://www.definder.net/shonky/
Definder - what does the word mean?
What is shonky?
...
Shonky - what is it?
A word that has been made up to mean another word for "Something that is not level "

D'après les photos... plusieurs occurrences p.e. :
https://www.asos.com/fr/asos-design/asos-design-robe-courte-...
https://www.emp-online.fr/p/robe-ourlet-à-volants/489151.htm...




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Note added at 1 heure (2021-08-08 16:38:42 GMT)
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errata corrige, per l'italiano:

orlo a balza

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Note added at 17 heures (2021-08-09 08:19:53 GMT)
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Differenza tra "shonky seames" e "asymmetric shonky seams":

https://www.amazon.in/PoshBery-Floral-Dress-Detail-shonky/dp...
https://www.amazon.in/PoshBery-Black-Dress-Asymmetric-shonky...