Unfashionable means not currently popular or stylish. When something is unfashionable, it's out of step with what most people think is cool or trendy right now. Bell-bottom jeans were fashionable in the 1970s but became unfashionable by the 1990s. A backpack style that everyone wanted last year might be unfashionable this year.

The word applies to more than just clothes. Ideas, hobbies, and ways of doing things can be unfashionable too. For a while, learning cursive handwriting seemed unfashionable as everyone focused on typing, though interest in it has returned. Certain music genres go in and out of fashion. Even baby names follow trends: names like Ethel and Herbert were once popular but became unfashionable for decades.

Being unfashionable isn't the same as being bad or wrong. Plenty of unfashionable things are perfectly good: they're just not what happens to be popular at the moment. Some people don't care much about fashion and happily wear or do unfashionable things. Others pay close attention to what's fashionable because they enjoy staying current. Either way, fashions change constantly, so today's unfashionable item might become fashionable again tomorrow.