smoothen

Lay this smooth upon the Cakes with a Knife, and smoothen it with a feather.

It was Frontenac's policy to appear to smoothen out the situation.

So you will start with sound pre-knowledge, which will smoothen the entire course of travel.

Surface grinding, in which the object is to remove metal or to smoothen surfaces.

Smoothing planes are, as the name implies, used to simply smoothen the work surface after it has been trued.