The word "un-allowable" refers to something that is not permitted or allowed. The antonyms for this word would be "allowable," "permissible," "acceptable," "approved," "legitimate," "legit," "legitimized," "legal," "authorized," "licensed," "sanctioned," "valid," "justified," "tolerated," and "admissible." These words signify that something is within the limits of what is permitted or considered acceptable under the given circumstances. In contrast to "un-allowable," these antonyms suggest that something is legitimate, valid, and warranted, abiding by established rules and conventions, and deemed appropriate and acceptable by the relevant authorities.