erratic

1 of 3

adjective

er·​rat·​ic i-ˈra-tik 

1

: having no fixed course : wandering

an erratic comet

2

a

: characterized by lack of consistency, regularity, or uniformity

erratic dieting

keeps erratic hours

b

: deviating from what is ordinary or standard : eccentric

an erratic genius

3

: transported from an original resting place especially by a glacier

an erratic boulder

4

archaic : nomadic

erratical

i-ˈra-ti-kəl 

adjective

erratically

i-ˈra-ti-k(ə-)lē 

adverb

erraticism

i-ˈra-tə-ˌsi-zəm 

noun

erratic

2 of 3

noun (1)

: 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

erraticism

3 of 3

noun (2)

er·​rat·​i·​cism

plural -s

: a state or instance of being erratic

especially : a wayward act or tendency

what erraticisms mere self-respect can lead to

—Edwin Kennebeck

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.

Synonyms of erratic

Adjective

• random
• scattered
• arbitrary

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

Adjective

Cynthia wants to get down to the bottom of Shamea’s erratic behavior, and the scene plays out like an angsty teen getting sent to the principal’s office. —Ile-Ife Okantah, Vulture, 15 June 2026

Later that same day, police in Texas stopped a vehicle driven by Taylor Parker for erratic driving near De Kalb. —Isabella Wandermurem, Time, 12 June 2026

Noun

For both amateur and professional geologists, the trail offers a close-up look at moraines, drumlins, eskers, erratics, kettles, kames and other glacial relics. —Joe Yogerst, Forbes.com, 15 Jan. 2026

Huge boulders — referred to as glacial erratics that were carried by glaciers during the last Ice Age — dot the landscape that’s forested with red maple, spruce and Canadian hemlock. —Jeanine Barone, Forbes, 5 Mar. 2025

Word History

Etymology

Adjective

Middle English erratik "wandering" (in the phrase erratik sterre "wandering star," i.e., a planet), borrowed from Latin errāticus "having no fixed position, wandering (of a heavenly body)," "wild, uncultivated (of a plant)," from errāre "to wander, roam, drift" + -āticus, adjective suffix of appurtenance — more at err, -age

Noun (1)

derivative of erratic entry 1

First Known Use

Adjective

14th century, in the meaning defined at sense 1

Noun (1)

circa 1623, in the meaning defined above

Rhymes for erratic

• asthmatic
• chromatic
• climatic
• dogmatic
• dramatic
• ecstatic
• emphatic
• eustatic
• fanatic
• hepatic
• lymphatic
• magmatic

Kids Definition

erratic

adjective

er·​rat·​ic

ir-ˈat-ik

1

: marked by lack of consistency or regularity

erratic dieting

2

: not of the usual or normal kind : eccentric

erratic behavior

erratically

-ˈat-i-k(ə-)lē

adverb

Medical Definition

erratic

adjective

er·​rat·​ic ir-ˈat-ik 

1

: characterized by lack of consistency, regularity, or uniformity

an erratic pulse

2

: deviating from what is ordinary or standard