Rule sets / NCAA / Illegal Feint Balk
Illegal Feint Balk
It varies by rule set but feints to first base are prohibited and a feint to third base might be as well.
If there is a runner or runners, a balk shall be called for the following action by a pitcher: While touching the pitcher's plate, any feinting motion without completing the throw toward the batter or toward first or third base.
Video examples
Pitcher feints a throw to first base.