The antonyms for the word "smooth out" include roughen, crumple, crease, wrinkle, ruffle, tousle, and rumple. When something is smooth, it means that it is free from bumps, lumps or any kind of unevenness. On the other hand, when it is rough, it means that it has a bumpy surface, rugged or irregular. When we wrinkle something, for example, we create small folds or creases on its surface, making it uneven. Tousling and rumpling make something disheveled or untidy. When we ruffle something, we create a series of small waves or ridges on the surface of a material. Therefore, depending on the context, choosing the right antonym for "smooth out" can help you convey a more precise meaning.