Countenanced means to approve or support something. Therefore, antonyms for "not countenanced" would be words that express approval or support. Some of the antonyms for "not countenanced" are sanctioned, endorsed, authorized, supported, backed, accepted, warranted, allowed, permitted, and advocated. These words imply an affirmative action or a nod of approval towards something. If something is "not countenanced", it is disapproved, prohibited or rejected. It is crucial to understand antonyms as they help in building vocabulary and language fluency. By using antonyms, we can express our ideas more clearly and effectively.