Something that is smooth, or that goes smoothly and easily.
"The negotiations went so smoothly that we signed the contract before lunch."
In plain English: A smooth surface is one that feels even and free of bumps or rough spots when you touch it.
"He put on some smooth to relax after his long day."
To make smooth or even.
"She carefully sanded down the rough edges of the wooden table until the surface was completely smooth."
In plain English: To smooth something means to make its surface even and free of rough spots or wrinkles.
"She smoothed her hair before going out."
having a surface free from roughness or bumps or ridges or irregularities
"smooth skin"
"a smooth tabletop"
"smooth fabric"
"a smooth road"
"water as smooth as a mirror"
of the margin of a leaf shape; not broken up into teeth
"The botanist noted that the margins of the hosta leaves were smooth, lacking any serrated edges or tiny teeth."
lacking obstructions or difficulties
"the bill's path through the legislature was smooth and orderly"
(of a body of water) free from disturbance by heavy waves
"a ribbon of sand between the angry sea and the placid bay"
"the quiet waters of a lagoon"
"a lake of tranquil blue water reflecting a tranquil blue sky"
"a smooth channel crossing"
"scarcely a ripple on the still water"
"unruffled water"
Having a texture that lacks friction. Not rough.
"The polished marble countertop felt incredibly smooth against my fingertips, offering no resistance at all."
In plain English: Smooth means having a surface that is even and free from bumps or rough spots.
Usage: Use smooth to describe surfaces with no bumps or ridges, such as polished wood or calm water. Avoid confusing it with soft; an object can be hard and still feel perfectly smooth against your skin.
Smoothly.
"The pianist played the final movement so smoothly that the audience held their breath until the very last note faded away."
In plain English: Smoothly means doing something without any problems, bumps, or delays.
"The car accelerated smoothly down the highway."
The word "smooth" comes from the Old English smēþe, which was borrowed into Middle English as smothe. Although its ultimate origin is unknown, it shares a common ancestor with related words in Germanic languages that also mean "smooth."