The word "officially" means in an authorized, formal, or sanctioned way. Some antonyms for "officially" are:
Unofficially: This is the most obvious opposite. When something is done unofficially, it is not authorized or sanctioned by an official body or authority. For example, "The news spread unofficially before the official announcement was made." Unofficially implies a lack of formal approval or recognition.
Informally: This suggests a more relaxed and casual way of doing things, without the formality and structure of official procedures. For instance, "The meeting was held informally over coffee, rather than in an official boardroom." Informally indicates a departure from the strictness and protocol of official settings.
Under the table: This phrase has a negative connotation and means in a secretive or illegal way that is contrary to official channels. For example, "Some deals are made under the table, away from official scrutiny." Under the table represents actions that are hidden and not in accordance with official rules and regulations.
In conclusion, these antonyms of "officially" highlight different ways of doing things that are not in an authorized or formal manner. Whether it's unofficially, informally, or under the table, they all stand in contrast to the proper and recognized way of doing things officially.