undependable

/ˌʌndɪˈpɛndəbəl/
unreliable

The old car was undependable, breaking down every few weeks.

The car was unreliable, failing frequently.


informal

Not able to be relied upon; unreliable.

Her boss called her undependable after she missed three deadlines in a row.

Her boss criticized her for missing deadlines repeatedly.

The weather forecast proved undependable, predicting sunshine but delivering rain.

The forecast was inaccurate, showing sunshine instead of rain.

Commonly used to describe people, systems, or things that fail to meet expectations consistently.

Collocations

undependable employeea worker who cannot be trusted to complete tasks reliablyundependable servicea service that frequently fails to deliver as promised

Pro Tip

Avoid confusion with 'unreliable'

'Undependable' emphasizes a lack of trustworthiness or consistency, while 'unreliable' can also refer to mechanical failure or unpredictability. Use 'undependable' for people or systems that fail to meet obligations.

Gold Rule

Use 'undependable' for people or systems

Reserve 'undependable' for contexts where reliability is expected, such as employees, services, or machinery. Avoid using it for abstract concepts like 'weather' unless emphasizing human failure (e.g., 'undependable weather forecasts').

Word Origin

Formed in English by adding the negative prefix 'un-' to 'dependable' (from 'depend' + '-able'). First recorded in the early 19th century.

Usage Notes

Used to criticize someone or something for failing to meet expectations. More common in informal contexts than formal writing.

Word Breakdown

un-
not
prefix
+
depend
to rely on
root
+
-able
capable of being
suffix
English Dictionary