breaking wind vs reflex action

breaking wind and reflex action both are nouns.

Word	Noun	Adjective	Verb	Adverb
breaking wind	Yes	No	No	No
reflex action	Yes	No	No	No

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

breaking wind (noun)	reflex action (noun)
a reflex that expels intestinal gas through the anus	an automatic instinctive unlearned reaction to a stimulus