belching vs reflex

belching and reflex both are nouns.

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

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

belching: a reflex that expels gas noisily from the stomach through the mouth
reflex: an automatic instinctive unlearned reaction to a stimulus

belching (noun)	reflex (noun)
a reflex that expels gas noisily from the stomach through the mouth	an automatic instinctive unlearned reaction to a stimulus
the forceful expulsion of something from inside

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