Okla. Stat. tit. 15, § 15-61: Undue influence defined

Undue influence consists:

1. In the use, by one in whom a confidence is reposed by

another, or who holds a real or apparent authority over him, of such

confidence or authority for the purpose of obtaining an unfair

advantage over him.

2. In taking an unfair advantage of another's weakness of

mind; or,

3. In taking a grossly oppressive and unfair advantage of

another's necessities or distress.