Self-evident, intuitively obvious.
Presumed without analysis.
Based on hypothesis and theory rather than experiment or empirical evidence.
Developed entirely from scratch, without deriving it from existing languages.
In a way based on theoretical deduction rather than empirical observation.
Not to be doubted or denied; established as a fact.
Unfailing; infallible.
Known but not specifically named; indeterminate; indefinite; one or some; sometimes used independently as a noun, and meaning certain persons; see also "one".
Fixed or stated; regular; determinate.
Sure, positive, not doubting.
Actually existing; sure to happen; inevitable.
Having been determined but not specified.
Unnamed or undescribed members (of).