What is the meaning of Brainwash?

A distorting effect upon one's memory, belief, or ideas, as by propaganda.

To affect one's mind by using extreme mental pressure or any other mind-affecting process. (e.g. hypnosis)

To take from an electronically controlled machine its stored-up information; to erase a computer's programming. (1960)

To persuade completely and forcibly.

Source: wiktionary.org