nonextant vs extinct

nonextant and extinct both are adjectives.

Word	Noun	Adjective	Verb	Adverb
nonextant	No	Yes	No	No
extinct	No	Yes	No	No

As adjectives, nonextant and extinct are synonyms defined as:

nonextant and extinct: no longer in existence; lost or especially having died out leaving no living representatives

nonextant (adjective)	extinct (adjective)
no longer in existence; lost or especially having died out leaving no living representatives	no longer in existence; lost or especially having died out leaving no living representatives
no longer existing or inaccessible through loss or destruction	(of e.g. volcanoes) permanently inactive
	being out or having grown cold