erratic
Americanadjective
-
deviating from the usual or proper course in conduct or opinion; eccentric.
erratic behavior.
- Synonyms:
- capricious, unstable, unpredictable
- Antonyms:
- stable, regular, consistent
-
inconsistent, irregular, or unpredictable.
Many factors affect purchasing power, such as inflation and erratic swings in the stock market.
-
having no certain or definite course or pattern; 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.
noun
-
an erratic or eccentric person.
-
Geology. an erratic boulder or the like.
adjective
-
irregular in performance, behaviour, or attitude; inconsistent and unpredictable
-
having no fixed or regular course; wandering
noun
-
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
Other Word Forms
Etymology
Origin of erratic
First recorded in 1325–75; Middle English, from Latin errāticus, equivalent to errāt(us) (past participle of errāre “to make a mistake, err” ( see err) + -icus -ic
Explanation
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.
Vocabulary lists containing erratic
List 1
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To Kill a Mockingbird
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"To Kill a Mockingbird" by Harper Lee, Chapters 1–6
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The region could see widespread rain, with a 10% to 20% chance of thunderstorms that could bring gusty, erratic winds and lightning by Wednesday, according to the National Weather Service in Oxnard.
From Los Angeles Times ● Oct. 19, 2026
"Sort of quite demanding and persuasive. I think erratic would be maybe a slightly better term."
From BBC ● Oct. 16, 2026
The actual writing of the recipes, however, can be erratic.
From The Wall Street Journal ● Oct. 16, 2026
The cyclical climate phenomenon raises surface temperatures in the central and eastern equatorial Pacific Ocean and causes global changes in winds and rainfall as well as erratic weather conditions.
From Barron's ● Sep. 28, 2026
During one collaboration, he and Philip Abelson were bedeviled by the erratic performance of an ionization chamber until Abelson noticed that its behavior corresponded to Kamen’s wanderings around the room.
From "Big Science" by Michael Hiltzik
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Get a wordDefinitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
