The word "sheetlike" refers to anything that resembles or is similar to a sheet in terms of its shape, size or texture. However, there are several antonyms or opposite words that can be used to describe things that are not sheetlike. Some of these include "round," "irregular," "curvy," "bulbous," "bumpy," "lumpy," "knobby," "wrinkled," "crinkled," "fluffy," "puffy," "fuzzy," "hairy," "spiky," "stiff," "rigid," "hard" and "rocky." These words are used to describe things that are not flat, smooth or uniform in shape or texture, and therefore, have a completely different property or quality from anything that is sheetlike.