supposition vs assumption

supposition and assumption both are nouns.

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

As nouns, supposition and assumption are synonyms defined as:

Other synonyms of supposition include supposal.

supposition (noun)	assumption (noun)
a hypothesis that is taken for granted	the act of taking possession of or power over something
the cognitive process of supposing	the act of assuming or taking for granted
a message expressing an opinion based on incomplete evidence	audacious (even arrogant) behavior that you have no right to
	a hypothesis that is taken for granted
	a statement that is assumed to be true and from which a conclusion can be drawn