involuntary vs reflex

involuntary is not a noun while reflex is a noun.

Word	Noun	Adjective	Verb	Adverb
involuntary	No	Yes	No	No
reflex	Yes	Yes	No	No

involuntary (noun)	reflex (noun)
	an automatic instinctive unlearned reaction to a stimulus

involuntary (adjective)	reflex (adjective)
not subject to the control of the will	without volition or conscious control
controlled by the autonomic nervous system; without conscious control