extinction vs defunctness

extinction and defunctness both are nouns.

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

As nouns, extinction and defunctness are synonyms defined as:

extinction (noun)	defunctness (noun)
the act of extinguishing; causing to stop burning	no longer in existence
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no longer active; extinguished