undependable
Likely to fail
Undependable describes someone or something you can't rely on.
An undependable car breaks down without warning.
An undependable friend cancels plans repeatedly.
The word implies a pattern rather than a single failure: He proved undependable when it mattered most.
Subject to sudden changes
- mercurialProne to sudden change
- volatileLiable to sudden change
- changeableCapable of alteration
- whimsicalPlayfully fanciful or erratic
flighty · erratic · impulsive · temperamental · inconstant · wavering · unsteady · moody
Not deserving of confidence
- flakyCrumbly or unreliable
- irresponsibleLacking sense of duty
- negligentFailing in due care
- carelessInattentive, prone to mistakes
forgetful · uncommitted · slipshod · lackadaisical · slapdash · undisciplined · derelict · lax
Lacking regularity or consistency
- sporadicOccurring irregularly, infrequently
- unpredictableCannot be anticipated
- fluctuatingShifting irregularly over time
- unevenNot smooth or balanced
irregular · patchy · intermittent · variable · hit-or-miss · unrepeatable · choppy · spotty
capricious
Subject to sudden changes
- mercurialProne to sudden change
- volatileLiable to sudden change
- changeableCapable of alteration
whimsical · flighty · erratic · impulsive · temperamental · inconstant · wavering · unsteady · moody · protean
untrustworthy
Not deserving of confidence
- flakyCrumbly or unreliable
- irresponsibleLacking sense of duty
- negligentFailing in due care
careless · forgetful · uncommitted · slipshod · lackadaisical · slapdash · undisciplined · derelict · lax · remiss
erratic
Lacking regularity or consistency
- sporadicOccurring irregularly, infrequently
- unpredictableCannot be anticipated
- fluctuatingShifting irregularly over time
uneven · irregular · patchy · intermittent · variable · hit-or-miss · unrepeatable · choppy · spotty · fitful
precarious
Dangerously insecure
iffy · dodgy · dubious · questionable · unstable · insecure · shaky · unproven · untested · unpredictable
undependabledependable
Worthy of trust
reliable · consistent · steady · sure · unfailing
undependabletrustworthy
Worthy of confidence
reliable · responsible · dependable · loyal · faithful
undependablesteadfast
Firmly loyal, unshakeable
undeviating · unwavering · steady · constant · stable
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