guar·an·tor \| ̷ ̷rən.|tȯ(ə)r, -ȯ(ə), ˈ ̷ ̷rəntə(r)\noun (-s) Etymology:guaranty (I) + -or 1.: one that guarantees < our Strategic Air Command is the guarantor of our security — Carl Spaatz > 2.: one that makes or gives a guaranty or surety : one that enters in a guaranty