improbable vs supposed

improbable and supposed both are adjectives.

Word	Noun	Adjective	Verb	Adverb
improbable	No	Yes	No	No
supposed	No	Yes	No	No

improbable (adjective)	supposed (adjective)
not likely to be true or to occur or to have occurred	required or under orders
having a probability too low to inspire belief	doubtful or suspect
too improbable to admit of belief	based primarily on surmise rather than adequate evidence
	mistakenly believed