uncertain vs doubtful

uncertain and doubtful both are adjectives.

Word	Noun	Adjective	Verb	Adverb
uncertain	No	Yes	No	No
doubtful	No	Yes	No	No

uncertain (adjective)	doubtful (adjective)
not established beyond doubt; still undecided or unknown	open to doubt or suspicion
lacking or indicating lack of confidence or assurance	fraught with uncertainty or doubt
not certain to occur; not inevitable	unsettled in mind or opinion
not established or confirmed
ambiguous (especially in the negative)
not consistent or dependable
subject to change