"Not countenance" is a strong expression suggesting opposition and disapproval. Some synonyms for this phrase are disapprove, condemn, rebuke, oppose, and reject. These words imply a clear stance against something or someone. Disapprove suggests disagreement or dislike of an action or behavior. Condemn emphasizes a stronger judgment of wrongdoing. Rebuke implies a reprimand or criticism for inappropriate conduct. Oppose denotes a resistance or objection to a proposal or idea. While reject connotes a decisive refusal or dismissal of something altogether. When using any of these synonyms, it's important to consider nuances and context to accurately convey one's disapproval.