unfashionable not popular or fashionable at the present time – used especially about people’s ideas, beliefs, and way of life:
They lived in an unfashionable part of London.
Marriage has become unfashionable in some countries.
out of fashion no longer fashionable – used especially about clothes, styles, and behaviour:
Miniskirts have been in and out of fashion over the years.
Leather jackets had never fallen out of fashion (=become unfashionable).
He used to be a smoker until smoking went out of fashion.
dated used for describing things which were fashionable and modern at one time but are starting to look unfashionable or old now:
The hotel needs to improve its dated interior.
The show seems dated now.
passé no longer fashionable – used especially about ways of doing and thinking about things. A rather formal use:
The musicals and light comedies for which she was known have become passé.
Some of his ideas about food are a bit passé.
something is so last year informal used when saying that something is now very unfashionable – a very informal use:
Blogging is already starting to feel so last year.
The resort is overcrowded and so last year.

[TahlilGaran] English Thesaurus ▲

out of fashion
• out of style/fashion
to be not fashionable, to be obsolete
The kind of jeans that my friend wears have been out of style for a long time now.

[TahlilGaran] English Idioms Dictionary ▲

out of fashion
adj. phr. Having passed from vogue; out of the current mode.
The miniskirt is now out of fashion in most quarters, but it may very well come back some day.

[TahlilGaran] English Idioms Dictionary ▲