This appears to be a typographical variant or misspelling of 'brainwashing'; the systematic attempt to change someone's beliefs through pressure, repetition, or isolation.
This appears to be a non-standard spelling; the correct form 'brainwashing' combines 'brain' and 'washing' with the gerund suffix '-ing', metaphorically describing belief-change like cleaning.
Even this misspelled variant shows how the metaphor of 'washing' the brain has saturated our language—we use cleaning metaphors for mental states so naturally that variations of the word still communicate the same idea.
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