Frilly describes something decorated with frills: ruffles, lace, or gathered fabric that creates waves, ripples, or fancy edges. A frilly dress might have layers of ruffles around the collar and sleeves. A frilly curtain has decorative gathered fabric along its edges instead of hanging straight and plain.

Frills are decorative rather than functional. They don't keep you warmer or make a curtain block light better. They're purely about appearance, adding a fancy, elaborate, or old-fashioned look. Victorian-era clothing was often extremely frilly, with ruffles on everything from shirts to undergarments.

The word often carries a sense of being overly decorated or unnecessarily fancy. When someone describes a restaurant as “too frilly,” they might mean it feels pretentious or overly formal. In writing, “frilly language” means using unnecessarily complex or flowery words when simpler ones would work better.

While frilly things can be beautiful and fun, especially for special occasions, the word sometimes suggests excess. A few ruffles might look elegant, but too many can feel overwhelming. That's why people sometimes use frilly to gently criticize something as being more decorative than it needs to be.