lavatory vs crapper

lavatory and crapper both are nouns.

Word	Noun	Adjective	Verb	Adverb
lavatory	Yes	No	No	No
crapper	Yes	No	No	No

As nouns, crapper is a hypernym of lavatory; that is, crapper is a word with a broader meaning than lavatory:

Other hypernyms of lavatory include can, commode, pot, potty, stool, throne, toilet.

lavatory (noun)	crapper (noun)
a room or building equipped with one or more toilets	a plumbing fixture for defecation and urination
a bathroom sink that is permanently installed and connected to a water supply and drainpipe; where you can wash your hands and face
a toilet that is cleaned of waste by the flow of water through it