Synonyms of the word

unfailing

• adj. inexhaustible.
• adj. changeless.
• adj. infallible.

constant

• adj. Unchanged through time or space; permanent.
• adj. Consistently recurring over time; persistent.
• adj. Steady in purpose, action, feeling, etc.
• adj. Firm; solid; not fluid.
• adj. (obsolete) Consistent; logical.
• n. That which is permanent or invariable.
• n. (algebra) A quantity that remains at a fixed value throughout a given discussion.
• n. (sciences) Any property of an experiment, determined numerically, that does not change under given circumstances.
• n. (computing) An identifier that is bound to an invariant value; a fixed value given a name to aid in readability…

foolproof

• adj. For a device: protected, or designed to be proof against misuse or error.
• adj. For an idea or plan: infallible, or bulletproof.
• v. (transitive) To make foolproof.

inexhaustible

• adj. Impossible to exhaust; unlimited.

infallible

• adj. Without fault or weakness; incapable of error or fallacy.
• adj. Certain, sure.

unflagging

• adj. Never tiring or lacking energy; without rest; without slowing.