= failure, n. 1. Obsolete except in phrase without fail; now used only to strengthen an injunction or a promise; formerly also with statements of…

Safely.

without lack: without defect, flaw, or fault, whether physical or moral; also, without fail. Obsolete.

Default, failing, neglect. without (any) fault (= French sans faute): without fail; hence, for a certainty. Cf. fail, n.2 1. Obsolete.

With certainty of result; efficaciously.

only in rhyming phrase without lipse, apparently = ‘without fail’.

With certainty, confidence, or assurance; esp. (with reference to knowledge or belief) for certain, undoubtingly (now somewhat archaic).

The action of fail, v., in various senses; an instance of this, a failure. †for, without (any) failing = for, without fail (see fail, n.1).

With certainty; without risk of failure. Now rare, except in (as) sure as —— at phrases 1 and sure enough at phrases 2a.

Without risk of error; with certainty.