Antonyms of adj unfailing

3 senses of unfailing

Sense 1
foolproof, unfailing -- (not liable to failure; "a foolproof identification system"; "the unfailing sign of an amateur"; "an unfailing test")

INDIRECT (VIA infallible) -> fallible -- (likely to fail or make errors; "everyone is fallible to some degree")

Sense 2
unfailing -- (always able to supply more; "an unfailing source of good stories"; "a subject of unfailing interest")

INDIRECT (VIA inexhaustible) -> exhaustible -- (capable of being used up)

Sense 3
unfailing, unflagging -- (unceasing; "unfailing loyalty"; "unfailing good spirits"; "unflagging courtesy")

INDIRECT (VIA constant) -> inconstant -- (likely to change frequently often without apparent or cogent reason; variable; "inconstant affections"; "an inconstant lover"; "swear not by...the inconstant moon"- Shakespeare)

Similarity of adj unfailing

3 senses of unfailing

Sense 1
foolproof, unfailing -- (not liable to failure; "a foolproof identification system"; "the unfailing sign of an amateur"; "an unfailing test")
       => infallible (vs. fallible) -- (incapable of failure or error; "an infallible antidote"; "an infallible memory"; "the Catholic Church considers the Pope infallible"; "no doctor is infallible")

Sense 2
unfailing -- (always able to supply more; "an unfailing source of good stories"; "a subject of unfailing interest")
       => inexhaustible (vs. exhaustible) -- (incapable of being entirely consumed or used up; "an inexhaustible supply of coal")

Sense 3
unfailing, unflagging -- (unceasing; "unfailing loyalty"; "unfailing good spirits"; "unflagging courtesy")
       => constant (vs. inconstant) -- (steadfast in purpose or devotion or affection; "a man constant in adherence to his ideals"; "a constant lover"; "constant as the northern star")