1 a : having a flat, even surface : not rough : not having any bumps, ridges, or uneven parts
▪ smooth skin ▪ They groomed the ski trail so it was smooth. ▪ The river rocks had been worn smooth by the water. ▪ The surface is (as) smooth as silk. [=very smooth]
b of a liquid mixture : not having any lumps : mixed together so there are no lumps
▪ Whisk the flour into the gravy until it is smooth. ▪ The milkshake was smooth and creamy. 2 : happening or done without any problems
▪ With the aid of observers, the election process was a smooth one. ▪ Our trip was smooth and uneventful. 3 a : even and regular without sudden movements
▪ the smooth movements of a swimmer ▪ She has a nice, smooth golf swing.
b : not having or causing sudden, violent movements
▪ His new car has a smooth ride. ▪ Our flight was very smooth. — opposite rough 4 informal : relaxed, confident, and pleasant in a way that may be intended to deceive people
▪ I don't trust him—he's just too smooth. ▪ He has a smooth manner. ▪ He's a real smooth talker. [=he says flattering things] ▪ She's a smooth operator. [=a person who is smooth] — see also smoothie 5 a : not sharp, bitter, or unpleasant in taste or smell
▪ The wine was full and smooth. ▪ a smooth cup of coffee
b : pleasant to hear or listen to
▪ He has a rich, smooth voice.