definite, definitive

Definite or definite means exact or precise; clearly defined--
We have no definite plans; we're just going to visit anyplace that seems interesting. 
Be sure to get definite directions, so we won't get lost.

Definite may also mean certain or sure--
We have no definite plans; we may stay home, or we may go out.
He won't give a definite answer; he just puts us off with vague comments.

Definitive or definitive, of a text or work of art, describes the most precise or exact version--
This is the definitive edition; it is an unedited transcription of the original manuscript.
Most people agree that the director's cut is the definitve version.

Definitive may also describe a statement that provides a specific or authoritative solution or answer to a dilemma--
Can we issue a definitve statement, one that will settle the controversy?
The manager has issued definitive instructions, so we'll all be doing it the same way.

Now that you know that, you can say--
"If you can't get him to make a definitve statement, try for a definite answer to a "yes or no" question."