anomalous

adjective

anom·​a·​lous ə-ˈnä-mə-ləs 

1

: inconsistent with or deviating from what is usual, normal, or expected : irregular, unusual

Researchers could not explain the anomalous test results.

2

a

: of uncertain nature or classification

an anomalous figure in the world of politics

b

: marked by incongruity or contradiction : paradoxical

anomalously adverb

anomalousness noun

Synonyms

• unusual
• extraordinary
• exceptional
• abnormal
• unique
• rare
• odd
• uncommon

Choose the Right Synonym for anomalous

irregular, anomalous, unnatural mean not conforming to rule, law, or custom.

irregular implies not conforming to a law or regulation imposed for the sake of uniformity in method, practice, or conduct.

concerned about his irregular behavior

anomalous implies not conforming to what might be expected because of the class or type to which it belongs or the laws that govern its existence.

her drive made her an anomalous figure in a sleepy organization

unnatural suggests what is contrary to nature or to principles or standards felt to be essential to the well-being of civilized society.

prisoners treated with unnatural cruelty

Examples of anomalous in a Sentence

Researchers could not explain the anomalous test results.

that was an anomalous year for the housing industry, so the number of starts is anything but typical

Recent Examples on the Web

Continuous monitoring is necessary, especially for detecting unauthorized API calls or user access, anomalous data flows or excessive account privileges. —Amir Khayat, Forbes.com, 5 Aug. 2025

Earth’s Leaky Core Hints that matter is somehow breaching the starkest density barrier within the planet began to emerge half a century ago, in the form of anomalous helium isotopes extracted from volcanic rock. —Quanta Magazine, 4 Aug. 2025

By Thursday, the anomalous high pressure is expected to weaken and then dissipate, increasing chances for rain. —Martin E. Comas, The Orlando Sentinel, 28 July 2025

In 2009, Chandra spotted anomalous X-rays originating from a region 40,000 light-years from the center of a giant elliptical galaxy called NGC 6099, which lies 453 million light-years from us. —Keith Cooper, Space.com, 25 July 2025

Word History

Etymology

Late Latin anōmalus "irregular (of grammatical paradigms), unequal in size (of planets)" (borrowed from Greek anṓmalos "not uniform, unequal, inconsistent, irregular [in grammar]," from an- an- + homalόs "even, uniform, equal, like") + -ous — more at similar

First Known Use

1606, in the meaning defined at sense 1

Phrases Containing anomalous

• unidentified anomalous phenomenon

Kids Definition

anomalous

adjective

anom·​a·​lous ə-ˈnäm-ə-ləs 

: not following a general rule or method : irregular, unusual

anomalously adverb

anomalousness noun

Medical Definition

anomalous

adjective

anom·​a·​lous ə-ˈnäm-ə-ləs 

: deviating from normal

anomalous development

anomalous pulmonary venous drainage

—Physicians' Current Procedural Terminology

specifically : having abnormal vision with respect to a particular color but not color-blind

she was almost red anomalous

—Nature