A priori is a Latin term that means "from the earlier." It's used in philosophy to describe knowledge that is obtained without experience, or that is independent of experience. Some synonyms for a priori include innate, instinctive, intuitive, inherent, and fundamental. These words all describe a type of knowledge or understanding that is 'built in' - it's not dependent on any external source, such as observation or experimentation. Another way to think of a priori knowledge is as something that is self-evident or axiomatic. Some people might also use words like preconceived or predetermined to describe a priori knowledge, as it implies a certain level of assumption or bias.