Other forms: frillily
Frilly things are lacy, decorative, or ruffled. A little girl might refuse to wear a frilly dress on the first day of school, preferring instead to wear overalls and purple rain boots.
Your grandma might have a favorite frilly apron that she wears when she bakes, and your cousin might dream of wearing a frilly white gown when she gets married. Frilly curtains are probably too cute and fussy for your kitchen if your decorating style is clean and modern. Even language can be described, figuratively, as frilly if it's showy or overly fancy.