Frilly is an adjective used to describe something that is lacey, ornamental or has excessive decoration. The antonyms for the word "frillier" are, therefore, words that describe something plain, simple, or without decoration. The simplest antonym for frilly is plain. Other antonyms for frilly could be understated, unadorned, unembellished, unornamented, and unpretentious. These qualities describe objects that are free of excess decoration, lace, or embellishments. In fashion, a minimalist or contemporary style is often the opposite of frilly. In conclusion, antonyms for frillier express the same qualities that make frilly objects over-decorated, ornate, or lacey.