Rigidbody.freezeRotation
var freezeRotation: bool;
bool freezeRotation;
freezeRotation as bool
Description

Controls whether physics will change the rotation of the object.

If freezeRotation is enabled, the rotation is not modified by the physics simulation. This is useful for creating first person shooters, because the player needs full control of the rotation using the mouse. See Also: Rigidbody.constraints.
	// Freeze the rotation
	rigidbody.freezeRotation = true;
using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void Example() {
        rigidbody.freezeRotation = true;
    }
}
import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def Example() as void:
		rigidbody.freezeRotation = true