defecation vs evacuation

defecation and evacuation both are nouns.

Word	Noun	Adjective	Verb	Adverb
defecation	Yes	No	No	No
evacuation	Yes	No	No	No

As nouns, evacuation is a hypernym of defecation; that is, evacuation is a word with a broader meaning than defecation:

Other hypernyms of defecation include elimination, excreting, excretion, voiding.

defecation (noun)	evacuation (noun)
the elimination of fecal waste through the anus	the act of removing the contents of something
	the act of evacuating; leaving a place in an orderly fashion; especially for protection
	the bodily process of discharging waste matter