taken_for_granted
1. [ adjective ] evident without proof or argument
Synonyms: self-evident axiomatic
Examples:

"an axiomatic truth" "we hold these truths to be self-evident"

Related terms: obvious
2. [ adjective ] accepted as real or true without proof
Synonyms: assumed assumptive
Examples:

"an assumed increase in population" "the assumed reason for his absence" "assumptive beliefs" "his loyalty was taken for granted"

Related terms: acknowledged