colonic irrigation vs enema

colonic irrigation and enema both are nouns.

Word	Noun	Adjective	Verb	Adverb
colonic irrigation	Yes	No	No	No
enema	Yes	No	No	No

As nouns, enema is a hypernym of colonic irrigation; that is, enema is a word with a broader meaning than colonic irrigation:

colonic irrigation: a water enema given to flush out the colon
enema: an injection of a liquid through the anus to stimulate evacuation; sometimes used for diagnostic purposes

Other hypernyms of colonic irrigation include clyster.

colonic irrigation (noun)	enema (noun)
a water enema given to flush out the colon	an injection of a liquid through the anus to stimulate evacuation; sometimes used for diagnostic purposes