1
Inconsistent behaviour
Changing unexpectedly in conduct, performance, or judgement.
Example
The driver's erratic behaviour prompted officials to stop the vehicle.
erratic
/ɪˈrætɪk/ · ih-RAT-ikadjective
Unpredictable, irregular, or inconsistent.
Use erratic when behaviour, movement, or measurements repeatedly depart from a stable or predictable pattern.
What erratic Really Means
The word becomes easier to use when its closely related senses are separated and compared.
2
Irregular pattern
Varying without a stable cycle, direction, or relationship.
Example
Erratic rainfall made harvests difficult to predict.
3
Unreliable measurements
Producing values that fluctuate unexpectedly and may indicate error or interference.
Example
The damaged sensor generated erratic readings throughout the test.
Use erratic Naturally
Notice how the surrounding noun or clause reveals the exact shade of meaning.
Erratic rainfall made harvests difficult to predict.
The instrument's erratic readings disappeared after its loose connection was repaired.
Funding arrived in erratic bursts rather than at regular intervals.
Precision Matters
Erratic overlaps with several common words, but each carries a different emphasis.
erratic
vs.Implies repeated irregular variation from an expected pattern.
unpredictable
Broadly means impossible to forecast, even when no irregular pattern is visible.
erratic
vs.Describes inconsistent behaviour, movement, or change.
haphazard
Describes an arrangement or method lacking a deliberate system.
erratic
vs.Can describe data, weather, motion, or behaviour.
mercurial
Especially describes sudden changes in mood, temperament, or attitude.
erratic
vs.Changes irregularly in value or direction.
sporadic
Occurs only occasionally or at scattered intervals.
Test erratic in Context
The measurements vary inconsistently and cannot be predicted from the conditions.
1
During calibration, the sensor alternated between plausible values and extreme spikes unrelated to any environmental change, producing ___ readings.