evacuation vs shitting

evacuation and shitting both are nouns.

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

As nouns, shitting is a hyponym of evacuation; that is, shitting is a word with a more specific, narrower meaning than evacuation:

Other hyponyms of evacuation include defecation, laxation, incontinence, incontinency, micturition, urination.

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