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 has accused Maduro of being an illegitimate president after an election that most independent observers believe was stolen. —Richard Hall, Time, 25 Oct. 2025

Many of the campaigns have been more classic—for example, earlier this year, a wave of fake GitHub pages appeared for LastPass, with hackers using SEO tactics on Google and Bing to boost the illegitimate pages. —PC Magazine, 25 Oct. 2025

Philosophical questions had not usually been regarded as illegitimate or meaningless—not, at least, by philosophers. —Literary Hub, 22 Oct. 2025

In addition, there is the servant Smerdyakov, presumed to be the illegitimate child of Fyodor and the intellectually disabled Lizaveta, nicknamed Stinking Lizaveta. —Karl Ove Knausgaard, New Yorker, 21 Oct. 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