conjectural vs conjecture

conjectural is not a noun while conjecture is a noun.

Word	Noun	Adjective	Verb	Adverb
conjectural	No	Yes	No	No
conjecture	Yes	No	Yes	No

conjectural (noun)	conjecture (noun)
	a hypothesis that has been formed by speculating or conjecturing (usually with little hard evidence)
	reasoning that involves the formation of conclusions from incomplete evidence
	a message expressing an opinion based on incomplete evidence

conjectural (adjective)	conjecture (adjective)
based primarily on surmise rather than adequate evidence

conjectural (verb)	conjecture (verb)
	to believe especially on uncertain or tentative grounds