These mental functions are to be suppressed. Suppression is a restraint. Suppression is not choking or curbing. It is not clamping down or crushing.
Viparyaya means misapprehension. Viparyaya is an unreal or perverse knowledge. There is an error or a mistake which is a misconception in understanding and that knowledge is unreal knowledge.
Verbal knowledge is the knowledge gathered about an object in the absence of that object.