na-adjective, noun which may take the genitive case particle 'no'
out of fashion; outdated; behind the times
Describes something that is no longer trendy or current, often used for clothing, ideas, or technology.
その服はもう流行遅れだ。
Those clothes are already out of fashion.
彼の考え方は流行遅れだと
I think his way of thinking is outdated.