collywobbles vs intestinal flu

collywobbles and intestinal flu both are nouns.

Word	Noun	Adjective	Verb	Adverb
collywobbles	Yes	No	No	No
intestinal flu	Yes	No	No	No

As nouns, intestinal flu is a hypernym of collywobbles; that is, intestinal flu is a word with a broader meaning than collywobbles:

collywobbles: severe gastroenteritis of unknown etiology; characterized by severe colic and vomiting and diarrhea
intestinal flu: inflammation of the stomach and intestines; can be caused by Salmonella enteritidis

Other hypernyms of collywobbles include gastroenteritis, stomach flu.

collywobbles (noun)	intestinal flu (noun)
severe gastroenteritis of unknown etiology; characterized by severe colic and vomiting and diarrhea	inflammation of the stomach and intestines; can be caused by Salmonella enteritidis