illegitimate

adjective

il·​le·​git·​i·​mate ˌi-li-ˈji-tə-mət 

1

a

: not recognized as lawful offspring

b

: born of parents not married to each other

2

a

: not sanctioned by law : illegal

b

: not authorized by good usage

c

of a taxon : published but not in accordance with the rules of the relevant international code

3

: not rightly deduced or inferred : illogical

4

: departing from the regular : erratic

illegitimately adverb

Synonyms

• baseborn
• misbegotten
• natural
• spurious
• supposititious
• unfathered

Examples of illegitimate in a Sentence

She thinks that my concerns are illegitimate.

They were fired from their jobs for illegitimate reasons.

Recent Examples on the Web

In January 2024, the work was sold to Geffen, seemingly on Sun’s behalf — Sun now says the sale was illegitimate. —Rachel Corbett, Vulture, 16 Apr. 2025

They get snared into helping their private investigator friend Moby (Hung) track down kidnappers intent on capturing a young woman named Sylvia (Lola Forner), who turns out to be the illegitimate daughter of a Spanish count. —ArsTechnica, 7 Apr. 2025

This helps ensure that customer trust isn’t eroded by the deleterious impact of misinformation disseminated by illegitimate word of mouth. —Branden Abushanab, Forbes, 14 Mar. 2025

Still, there's something so satisfying when Fisk lifts the sandwich wrapper to reveal pictures of Gallo's lover and illegitimate son. —Tommy Tuberville, Newsweek, 6 Mar. 2025

Word History

First Known Use

1536, in the meaning defined at sense 1a

Rhymes for illegitimate

• legitimate

Kids Definition

illegitimate

adjective

il·​le·​git·​i·​mate ˌil-i-ˈjit-ə-mət 

1

: born of a father and mother who are not married

2

: illegal

illegitimately adverb

Legal Definition

illegitimate

adjective

il·​le·​git·​i·​mate ˌi-li-ˈji-tə-mət 

1

: not recognized by the law as offspring

specifically : born out of marriage

Note: An illegitimate child is usually legitimated by his or her parents' later marriage. Illegitimate children generally have the same inheritance rights under intestate successions as legitimate children; statutes limiting their inheritance rights have been found to violate the equal protection clause.

2

: not valid according to law

illegitimate noun