Antonyms for the term "kept abreast of" would include "uninformed", "ignorant", "unaware", "uneducated", and "out of touch". These terms convey a distinct lack of knowledge or awareness on a particular subject matter. When not staying updated, individuals may miss out on crucial information that could impact their decisions, actions or overall success. It is important to stay informed and up-to-date in various aspects of life, such as current events, trends, and changes in industry and technology. Failure to do so may result in missed opportunities and have negative consequences.