defunctness vs extinction

defunctness and extinction both are nouns.

Word	Noun	Adjective	Verb	Adverb
defunctness	Yes	No	No	No
extinction	Yes	No	No	No

As nouns, defunctness and extinction are synonyms defined as:

defunctness (noun)	extinction (noun)
no longer in existence	the act of extinguishing; causing to stop burning
	a conditioning process in which the reinforcer is removed and a conditioned response becomes independent of the conditioned stimulus
	complete annihilation
	the reduction of the intensity of radiation as a consequence of absorption and radiation
	no longer in existence
	no longer active; extinguished