flushless toilet vs toilet

flushless toilet and toilet both are nouns.

Word	Noun	Adjective	Verb	Adverb
flushless toilet	Yes	No	No	No
toilet	Yes	No	No	No

As nouns, toilet is a hypernym of flushless toilet; that is, toilet is a word with a broader meaning than flushless toilet:

flushless toilet: a toilet that relies on bacteria to break down waste matter (instead of using water)
toilet: a plumbing fixture for defecation and urination

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

flushless toilet (noun)	toilet (noun)
a toilet that relies on bacteria to break down waste matter (instead of using water)	the act of dressing and preparing yourself
	a room or building equipped with one or more toilets
	a plumbing fixture for defecation and urination
	misfortune resulting in lost effort or money