adjective / noun
illegitimate
il-uh-JIT-uh-mut/ˌɪləˈdʒɪtəmət/
Not recognized as lawful or justified under prevailing rules.
The fake permit is illegitimate, with a stamp that fails to match official records.

Etymology
The base comes from a verb meaning “make lawful.” Its negative first described birth outside lawful marriage, then broadened to things lacking authorization or accepted standing.
In context
It’s either valid or invalid or legitimate or illegitimate, just or unjust on its own terms.
More examples
- Protesters call the government illegitimate because the election was rigged.
- Personal expenses are an illegitimate use of these public funds.
- Calling a child an illegitimate is dated and often offensive.
Forms
illegitimate · illegitimates
illegitimacy noun — The state of lacking lawful or justified standing.
illegitimately adverb — In a way lacking lawful or justified standing.
Similar words
- unlawful
- Specifically violates the law, rather than merely lacking justification.
- invalid
- Lacks legal force or fails to meet required standards.
- unjustified
- Lacks adequate reasons or evidence, without necessarily violating rules.