Being "up on" something means being familiar or knowledgeable about it. There are various synonyms for this phrase, such as "informed," "aware," "well-versed," "up-to-date," "knowledgeable," and "familiar." All these words signify a level of expertise or familiarity with a particular subject or situation. When you are "up on" something, you have the necessary information to make informed decisions or judgments. Being "up on" current events, technology, or industry developments can help you stay competitive and succeed in your field. It is essential to keep yourself "up on" the latest trends and updates, no matter which field you belong to.