The term "au courant" refers to being up-to-date or well-informed about a particular subject or topic. Some antonyms for this word include outdated, obsolete, antiquated, irrelevant, and uninformed. Not keeping up with the latest trends, news, and developments can lead to being out of touch with what's happening in the world. It's essential to stay knowledgeable and abreast of current events to engage in meaningful conversations and make informed decisions. Being in the know is crucial to succeeding in today's fast-paced society, where knowledge is power, and staying up-to-date is crucial.