irregular

1 of 2

adjective

ir·​reg·​u·​lar i-ˈre-gyə-lər 

ˌi(r)-

1

a

: not being or acting in accord with laws, rules, or established custom

irregular conduct

b

: not conforming to the usual pattern of inflection

irregular verbs

specifically : strong sense 16

c

: not following a usual or prescribed procedure

especially, British : celebrated without either proclamation of the banns or publication of intention to marry

irregular marriage

2

: not belonging to or a part of a regular organized group

specifically : not belonging to a regular army but raised for a special purpose

irregular troops

3

a

: lacking perfect symmetry or evenness

an irregular coastline

b

: having one or more floral parts of the same whorl different in size, shape, or arrangement

specifically : zygomorphic

4

: lacking continuity or regularity especially of occurrence or activity

irregular employment

irregularly adverb

irregular

2 of 2

noun

: one that is irregular: such as

a

: a soldier who is not a member of a regular military force

b

irregulars plural : merchandise that has minor defects or that falls next below the manufacturer's standard for firsts

Synonyms

Adjective

• abnormal
• unnatural

Choose the Right Synonym for irregular

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 irregular in a Sentence

Adjective

His behavior as a teacher was highly irregular.

Her application was handled in an irregular manner.

a very jagged, irregular surface

The stone has an irregular shape.

He has a very irregular schedule.

The festival has been held at irregular intervals.

Recent Examples on the Web

Adjective

This model features fall detection, irregular heart rate and rhythm notifications, and access to virtually the same apps. —Jade Chung-Lee, PC Magazine, 12 July 2025

Surveillance flights over the property detected an irregular field behind the house. —Ana María Cañizares, CNN Money, 11 July 2025

Noun

The existence of the irregulars raises an important question: How small can a galaxy get? —Phil Plait, Scientific American, 8 May 2025

The moons, observed from 2019 to 2021 at the Canada-France-Hawaii Telescope, were placed into subgroups within two categories of Saturnian irregulars; the Inuit group contains the Kiviuq and Siarnaq subgroups, and the Norse group contains the Phoebe, Mundilfari, and Kari subgroups. —Jack Knudson, Discover Magazine, 17 Mar. 2025

Word History

Etymology

Adjective

Middle English irreguler, from Anglo-French, from Late Latin irregularis not in accordance with rule, from Latin in- + regularis regular

First Known Use

Adjective

14th century, in the meaning defined at sense 1a

Noun

15th century, in the meaning defined above

Rhymes for irregular

• regular

Kids Definition

irregular

1 of 2 adjective

ir·​reg·​u·​lar (ˈ)ir-ˈ(r)eg-yə-lər 

1

a

: not following custom or rule

b

: not belonging to a recognized or organized body

irregular troops

2

a

: not following the normal or usual manner of inflection

the irregular verb "sell"

b

: strong sense 12

the irregular verb "write"

3

a

: having one or more like parts unequal in size, form, or the way they are arranged

irregular flowers

b

: uneven

4

: not continuous or regular in occurrence

at irregular intervals

irregularly adverb

irregular

2 of 2 noun

1

: an irregular soldier

2

: merchandise that is slightly imperfect

Medical Definition

irregular

adjective

ir·​reg·​u·​lar (ˈ)ir-ˈ(r)eg-yə-lər 

1

: lacking perfect symmetry of form : not straight, smooth, even, or regular

irregular teeth

2

a

: lacking continuity or regularity of occurrence, activity, or function

irregular breathing

b

of a physiological function : failing to occur at regular or normal intervals

irregular menstruation

have your bowels been irregular

c

of an individual : failing to defecate at regular or normal intervals

was constipated and very irregular

irregularly adverb

Legal Definition

irregular

adjective

ir·​reg·​u·​lar ir-ˈre-gyə-lər 

: not in accord with laws, rules, procedures, or established custom

irregularly adverb