uncertain vs iffy

uncertain and iffy both are adjectives.

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

uncertain (adjective)	iffy (adjective)
not established beyond doubt; still undecided or unknown	subject to accident or chance or change
lacking or indicating lack of confidence or assurance
not certain to occur; not inevitable
not established or confirmed
ambiguous (especially in the negative)
not consistent or dependable
subject to change