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er·​rat·​ic i-ˈra-tik How to pronounce erratic (audio)
: having no fixed course : wandering
an erratic comet
: characterized by lack of consistency, regularity, or uniformity
erratic dieting
keeps erratic hours
: deviating from what is ordinary or standard : eccentric
an erratic genius
: transported from an original resting place especially by a glacier
an erratic boulder
archaic : nomadic
erratical adjective
erratically adverb
erraticism noun


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: one that is erratic (see erratic entry 1)
especially : a boulder or block of rock transported from its original resting place especially by a glacier

Did you know?

Erratic can refer to literal "wandering". A missile that loses its guidance system may follow an erratic path, and a river with lots of twists and bends is said to have an erratic course. Erratic can also mean "inconsistent" or "irregular". So a stock market that often changes direction is said to be acting erratically; an erratic heartbeat can be cause for concern; and if your car idles erratically it may mean that something's wrong with the spark-plug wiring.

Choose the Right Synonym for erratic

strange, singular, unique, peculiar, eccentric, erratic, odd, quaint, outlandish mean departing from what is ordinary, usual, or to be expected.

strange stresses unfamiliarity and may apply to the foreign, the unnatural, the unaccountable.

a journey filled with strange sights

singular suggests individuality or puzzling strangeness.

a singular feeling of impending disaster

unique implies singularity and the fact of being without a known parallel.

a career unique in the annals of science

peculiar implies a marked distinctiveness.

the peculiar status of America's First Lady

eccentric suggests a wide divergence from the usual or normal especially in behavior.

the eccentric eating habits of preschoolers

erratic stresses a capricious and unpredictable wandering or deviating.

a friend's suddenly erratic behavior

odd applies to a departure from the regular or expected.

an odd sense of humor

quaint suggests an old-fashioned but pleasant oddness.

a quaint fishing village

outlandish applies to what is uncouth, bizarre, or barbaric.

outlandish fashions of the time

Examples of erratic in a Sentence

Adjective My sinker has been my most erratic pitch. And when your foundation pitch is lacking, you have to go to other pitches. My sinker has been in and out, but mostly out. Orel Hershiser, in New York Times, 9 May 1999
In winning his two-month match in Yugoslavia against Boris Spassky, 10 games to five, Bobby Fischer was erratic, which was hardly surprising considering his two-decade layoff, but there were times when he played more brilliantly than anybody could have expected. Sports Illustrated, 16 Nov. 1992
Over the centuries, in erratic ways, men have constructed a world in which they are relatively free of many kinds of threatening or harmful stimuli … B. F. Skinner, Beyond Freedom and Dignity, (1971) 1972
so far your effort to land a summer job has been very erratic because of your erratic attendance at practice, you're in danger of being cut from the team
Recent Examples on the Web
Another major contributor to overactive bladder syndrome in both women and men is detrusor overactivity—erratic contractions of the bladder muscle that send false signals of fullness to the brain. Emily Underwood, Smithsonian Magazine, 5 June 2024 That volatility created frustration within Anglo, where years of erratic performance eroded returns from more coveted commodities, such as copper. Eva Roytburg, Fortune Europe, 4 June 2024
Car-sized erratics embedded in ice were carried both within the lake area and as much as 500 miles from the lake by flood waters—some of the erratics weighed up to eight and a half tons. Keely Larson, Ars Technica, 4 Jan. 2023 Speidel was inspired to create these artworks from her fascination with glacial erratics, a type of rock that once was carried inside glacial ice and traveled hundreds of miles sometimes across thousands of years to its current resting spot. Nickole Kerner Bobley, Houston Chronicle, 25 Apr. 2020 See all Example Sentences for erratic 

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'erratic.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Adjective and Noun

Middle English, from Latin erraticus, from erratus, past participle of errare — see err

First Known Use


14th century, in the meaning defined at sense 1


circa 1623, in the meaning defined above

Time Traveler
The first known use of erratic was in the 14th century

Dictionary Entries Near erratic

Cite this Entry

“Erratic.” Dictionary, Merriam-Webster, Accessed 18 Jun. 2024.

Kids Definition


: marked by lack of consistency or regularity
erratic dieting
: not of the usual or normal kind : eccentric
erratic behavior

Medical Definition


er·​rat·​ic ir-ˈat-ik How to pronounce erratic (audio)
: characterized by lack of consistency, regularity, or uniformity
an erratic pulse
: deviating from what is ordinary or standard

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