Axiomatic (adjective)

1. Self-evident or accepted as true without proof.
2. Forming a universally accepted principle or rule.

Origin:

From the greek word "axiōma" meaning "self-evident truth".

Examples:

1. It is axiomatic that the sun will rise in the east.
2. The axiomatic nature of the principle made it difficult to argue against.
3. The theory was based on several axiomatic assumptions.
4. The statement was so axiomatic that it required no further explanation.
5. The axiomatic truth of the statement was undeniable.