ambiguous / ambivalent
Unclear meaning versus mixed feeling.
Ambiguous describes words, signals, or situations that can be read more than one way. Ambivalent describes a person who holds opposing feelings at once. A sentence is ambiguous. A voter may be ambivalent. Do not call a person ambiguous when you mean torn, or a sentence ambivalent when you mean unclear.
Examples
Use The last clause is ambiguous.
Use She was ambivalent about selling the house.
Avoid She was ambiguous about selling the house. (Unless her words, not her feelings, were unclear.)