supposition vs basis

supposition and basis both are nouns.

Word	Noun	Adjective	Verb	Adverb
supposition	Yes	No	No	No
basis	Yes	No	No	No

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

supposition: a hypothesis that is taken for granted
basis: the fundamental assumptions from which something is begun or developed or calculated or explained

supposition (noun)	basis (noun)
a hypothesis that is taken for granted	the fundamental assumptions from which something is begun or developed or calculated or explained
the cognitive process of supposing	a relation that provides the foundation for something
a message expressing an opinion based on incomplete evidence	the most important or necessary part of something