'Amenable' means open to persuasion, responsive to advice, or agreeable. When you say someone is 'amenable to reason', you mean they're willing to listen to logical arguments and can be persuaded through rational discussion - they're reasonable and flexible. 'Ambiguous' means unclear (also misspelled as 'ambigous'), 'ambivalent' means having mixed feelings, 'afoot' means in progress or happening, and 'aghast' means shocked - none of which fit being open to reasoned argument.