The phrase "not vital" can refer to something that is not essential or indispensable. Some synonyms for this phrase are optional, nonessential, trivial, unnecessary, inconsequential, and supplemental. When we say that something is not vital, it means that it is not necessary for the basic functioning of something or someone. For example, a hat may be not vital for walking outside on a sunny day, but it can be useful for protecting the eyes and skin from harmful UV rays. In any case, understanding synonyms for certain phrases can expand our vocabulary and help us communicate more effectively.