reflex vs automatic

reflex and automatic both are nouns.

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

As adjectives, reflex and automatic are synonyms defined as:

Other synonyms of reflex include reflexive.

reflex (noun)	automatic (noun)
an automatic instinctive unlearned reaction to a stimulus	self-loading rifle capable of automatic fire
	a pistol that will keep firing until the ammunition is gone or the trigger is released

reflex (adjective)	automatic (adjective)
without volition or conscious control	operating with minimal human intervention; independent of external control
	without volition or conscious control
	resembling the unthinking functioning of a machine