ne plus ultra vs polish

ne plus ultra and polish both are nouns.

Word	Noun	Adjective	Verb	Adverb
ne plus ultra	Yes	No	No	No
polish	Yes	No	Yes	No

As nouns, polish is a hyponym of ne plus ultra; that is, polish is a word with a more specific, narrower meaning than ne plus ultra:

ne plus ultra: the state of being without a flaw or defect
polish: a highly developed state of perfection; having a flawless or impeccable quality

Other hyponyms of ne plus ultra include couth, dream, cultivation, culture, finish, refinement, fare-thee-well, intactness, immaculacy.

ne plus ultra (noun)	polish (noun)
the state of being without a flaw or defect	the property of being smooth and shiny
	a highly developed state of perfection; having a flawless or impeccable quality
	a preparation used in polishing

ne plus ultra (verb)	polish (verb)
	bring to a highly developed, finished, or refined state
	improve or perfect by pruning or polishing
	make (a surface) shine