The noun form of the adjective smooth is smoothness.
- The noun 'smoothness' is an abstract noun as a Word for a state of occurring without problems or difficulty; a Word for a concept.
- The noun 'smoothness' is a concrete noun as a Word for a state of free from projections or unevenness of surface, not rough; a Word for a physical property.
The noun form of the verb to smooth is the gerund, smoothing.
- The noun 'smoothing' is an abstract noun as a Word for an act of relieving problems or difficulties; a Word for a concept.
- The noun 'smoothing' is a concrete noun as a Word for an act of removing physical imperfections from something; a Word for a physical act.
