Smooth : having an even and regular surface; free from perceptible projections, lumps, or indentations.Hard : solid, firm, and rigid; not easily broken, bent, or pierced.Rough : having an uneven or irregular surface; not smooth or level.Flat : having a level surface; without raised areas or indentations.Tough : (of a substance or object) strong enough to withstand adverse conditions or rough handling.Antonym of Smooth is Rough