Thin underlayer

SLIP

This garment often goes unnoticed but helps prevent wrinkles or bunching when worn beneath dresses or skirts. Think of something smooth and lightweight.

A "thin underlayer" hints at something placed beneath for smoothness or protection, like a slip—a lightweight garment worn under dresses or skirts. The word "slip" also fits as a verb meaning to slide, reinforcing the idea of something thin and smooth. Crossword clues often play on double meanings, and here "underlayer" cleverly points to both the noun and the function of the answer.