Frumpy describes clothing or appearance that looks outdated, dull, and unflattering. Someone dressed in frumpy clothes might be wearing shapeless, baggy garments in boring colors that don't fit well or look stylish. A frumpy outfit makes the person look dowdy and unstylish, like they grabbed whatever was easiest without thinking about how it looks.

The word carries a somewhat unkind edge. You probably wouldn't call someone frumpy to their face because it can sound like you're judging them for not caring about their appearance or not knowing how to dress well. A character in a book might start out frumpy before a makeover, wearing oversized sweaters and unflattering pants. Or someone might look at their old school photos and laugh at their frumpy clothes from years ago.

People sometimes feel frumpy when they're tired or haven't had time to put themselves together. The opposite of frumpy would be stylish, sharp, or put-together. Some people prefer not to look frumpy when they have a choice.