WordNet sense 1 (not brought to a conclusion; subject to further thought):

open, undetermined, unresolved

WordNet sense 2 (still in doubt):

unsettled

WordNet sense 3 (characterized by indecision):

on the fence

WordNet sense 4 (characterized by lack of decision and firmness):

indecisive

WordNet sense 5 (not bound or pledged):

uncommitted