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

an illegitimate government

… a retaliatory, harassing, or other illegitimate motive.

—Diamond "D" Const. Corp. v. McGowan, 282 F. 3d 191 (2002)

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 reasonable or fair

were fired for illegitimate reasons

4

: not rightly deduced or inferred : illogical

5

: departing from the regular : erratic

illegitimately adverb

Synonyms of illegitimate

• 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

So Maduro is an illegitimate leader. —NBC news, 11 Jan. 2026

Maduro was an illegitimate despot who had violated every agreement, including one in 2023 with the Biden administration, which proposed to lift sanctions in exchange for holding free and fair elections. —Garry Kasparov, The Atlantic, 10 Jan. 2026

Like Noriega, Maduro’s administration had been deemed thoroughly illegitimate by Western countries years earlier, and there had been many attempts from both within and without Venezuela to overthrow his government, spearheaded by US allies like Juan Guaidó and Maria Corina Machado. —Séamus Malekafzali, Washington Post, 8 Jan. 2026

Trump took decisive action Saturday in launching precision military strikes in Venezuela that enabled special forces to seize and detain Maduro, an illegitimate leader despised by his own people. —Lauren Green, The Washington Examiner, 5 Jan. 2026

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