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

• spurious
• misbegotten
• supposititious
• adopted
• natural
• orphaned

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

Trump’s comments came as Secretary of State Marco Rubio announced sanctions against U.N. official Francesca Albanese, accusing her of pushing illegitimate efforts at the International Criminal Court targeting U.S. and Israeli leaders. —Samantha-Jo Roth, The Washington Examiner, 9 July 2025

And then, on top of it, I was born out of some affair like some illegitimate, sinful mistake? —Brie Stimson, FOXNews.com, 28 June 2025

In addition to frequent password updates, individuals will need to be more alert about the increasing amount of malware hiding in illegitimate software, applications and other downloadable files, Valenzuela said. —Dylan Butts, CNBC, 26 June 2025

As a result, many patients internalize the belief that their suffering is exaggerated or illegitimate, creating uncertainty around when and how to chart a pain-free path forward. —Christy Saia-Owenby, Forbes.com, 20 June 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