unresolved vs undecided

unresolved and undecided both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unresolved	No	Yes	No	No
undecided	No	Yes	No	No

As adjectives, unresolved and undecided are synonyms defined as:

unresolved and undecided: not brought to a conclusion; subject to further thought

Other synonyms of unresolved include open, undetermined.

unresolved (adjective)	undecided (adjective)
not solved	characterized by indecision
characterized by musical dissonance; harmonically unresolved	not yet having made a commitment
not brought to a conclusion; subject to further thought	not brought to a conclusion; subject to further thought