smoothen vs polish

smoothen is not a noun while polish is a noun.

Word	Noun	Adjective	Verb	Adverb
smoothen	No	No	Yes	No
polish	Yes	No	Yes	No

As verbs, smoothen and polish are synonyms defined as:

Other synonyms of smoothen include shine, smooth.

smoothen (noun)	polish (noun)
	the property of being smooth and shiny
	a highly developed state of perfection; having a flawless or impeccable quality
	a preparation used in polishing

smoothen (verb)	polish (verb)
become smooth	bring to a highly developed, finished, or refined state
make smooth or smoother, as if by rubbing	improve or perfect by pruning or polishing
make (a surface) shine	make (a surface) shine