deviating from the usual or proper course in conduct or opinion; eccentric; queer: erratic behavior.
having no certain or definite course; wandering; not fixed: erratic winds.
Geology. noting or pertaining to a boulder or the like carried by glacial ice and deposited some distance from its place of origin.
(of a lichen) having no attachment to the surface on which it grows.


an erratic or eccentric person.
Geology. an erratic boulder or the like.

Origin of erratic

1325–75; Middle English < Latin errāticus, equivalent to errāt(us) (past participle of errāre to err) + -icus -ic
Related formser·rat·i·cal·ly, adverber·rat·i·cism, nounnon·er·rat·ic, adjective, nounnon·er·rat·i·cal·ly, adverbun·er·rat·ic, adjective
Can be confusederotic erratic exotic

Synonyms for erratic

Antonyms for erratic Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for erratically

carelessly, unevenly, capriciously, eccentrically

Examples from the Web for erratically

Contemporary Examples of erratically

  • She quits her job as governor—some might say erratically—and supporters applaud her courage.

    The Daily Beast logo
    Why Palin Mania Won't Die

    Matt Latimer

    October 15, 2009

Historical Examples of erratically

  • They found a place where saltpeter was very thinly and erratically distributed.

    Space Prison

    Tom Godwin

  • If He is merciful at all He cannot be merciful only spasmodically, erratically, or temporarily.

  • Halvard was propelling them vigorously but erratically forward.

    Wild Oranges

    Joseph Hergesheimer

  • Down plunged the vanquished monoplane, spirally, erratically.

    Billy Barcroft, R.N.A.S.

    Percy F. Westerman

  • The flat pointed head seems to be in contact with the ground or very near to it as the animal moves about rapidly and erratically.

British Dictionary definitions for erratically



irregular in performance, behaviour, or attitude; inconsistent and unpredictable
having no fixed or regular course; wandering


a piece of rock that differs in composition, shape, etc, from the rock surrounding it, having been transported from its place of origin, esp by glacial action
an erratic person or thing
Derived Formserratically, adverb

Word Origin for erratic

C14: from Latin errāticus, from errāre to wander, err
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for erratically



late 14c., "wandering, moving," from Old French erratique (13c.) and directly from Latin erraticus "wandering, straying, roving," from erratum "an error, mistake, fault," past participle of errare "to wander, err" (see err). Sense of "irregular, eccentric" is attested by 1841. The noun is from 1620s, of persons; 1849, of boulders. Related: Erratically.

Online Etymology Dictionary, © 2010 Douglas Harper