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erratic

The adjective erratic describes things that are unpredictable, unusual, and that deviate from the norm. An erratic quarterback might completely confuse his receivers waiting for a pass.

Like its linguistic relative, error, the adjective erratic means "deviating from the norm," or "wrong." It also implies behavior or qualities that are unpredictable or odd. The word comes from the Latin verb errare, or "to wander" off course. In the field of geology, a rock that is erratic is unlike others in its environment because it has been transported by glacial activity. Likewise, someone driving a car that veers out of its lane is said to be driving erratically.

Definitions of erratic
  1. adjective
    liable to sudden unpredictable change
    erratic behavior”
    synonyms: fickle, mercurial, quicksilver
    changeable, changeful
    such that alteration is possible; having a marked tendency to change
  2. adjective
    likely to perform unpredictably
    erratic winds are the bane of a sailor”
    synonyms: temperamental, wayward
    undependable, unreliable
    not worthy of reliance or trust
  3. adjective
    having no fixed course
    “an erratic comet”
    synonyms: planetary, wandering
    unsettled
    not settled or established
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