Actually existing; sure to happen; inevitable.
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.
Not to be doubted or denied; established as a fact.
Sure, positive, not doubting.
Having been determined but not specified.
Unnamed or undescribed members (of).
Unavoidable, inevitable.
Required, essential, whether logically inescapable or needed in order to achieve a desired result or avoid some penalty.