guess vs suppose

guess is a noun but suppose is not a noun.

Word	Noun	Adjective	Verb	Adverb
guess	Yes	No	Yes	No
suppose	No	No	Yes	No

As verbs, guess and suppose are synonyms defined as:

Other synonyms of guess include imagine, opine, reckon, think.

guess (noun)	suppose (noun)
an estimate based on little or no information
a message expressing an opinion based on incomplete evidence

guess (verb)	suppose (verb)
expect, believe, or suppose	expect, believe, or suppose
judge tentatively or form an estimate of (quantities or time)	to believe especially on uncertain or tentative grounds
guess correctly; solve by guessing	require as a necessary antecedent or precondition
put forward, of a guess, in spite of possible refutation	take for granted or as a given; suppose beforehand
	express a supposition