sneezing vs reflex

sneezing and reflex both are nouns.

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

As nouns, reflex is a hypernym of sneezing; that is, reflex is a word with a broader meaning than sneezing:

sneezing: a symptom consisting of the involuntary expulsion of air from the nose
reflex: an automatic instinctive unlearned reaction to a stimulus

sneezing (noun)	reflex (noun)
a symptom consisting of the involuntary expulsion of air from the nose	an automatic instinctive unlearned reaction to a stimulus

sneezing (adjective)	reflex (adjective)
	without volition or conscious control