impermissible

American  

[im-per-mis-uh-buhl] / ˌɪm pərˈmɪs ə bəl /

adjective

1. not permissible or allowable; unallowable.

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impermissible British  

/ ˌɪmpəˈmɪsɪbəl /

adjective

1. not permissible; not allowed

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Other Word Forms

• impermissibility noun
• impermissibly adverb

Etymology

Origin of impermissible

First recorded in 1855–60; im- ² + permissible

Explanation

Something impermissible isn't allowed. It's impermissible in every part of the U.S. to drive 100 miles an hour on the highway. Things that are permissible are legal, authorized, or welcome — you are permitted to do them. The opposite of permissible is impermissible, which adds the "opposite" prefix im- to permissible, from the Latin permittere, "let, allow, grant, or permit." It's impermissible to bully other kids at school, or against the rules, and it's impermissible to steal a car, or against the law.

Example Sentences

This was related to separate charges involving impermissible contact to register academy players between 2019 and 2022.

From BBC • Mar. 16, 2026

Chamber of Commerce, said swift “refunds of the impermissible tariffs” would help more than 200,000 small-business importers.

From The Wall Street Journal • Feb. 22, 2026

Circuit Court of Appeals held in 2022 that “the prosecution of foreign nationals traveling on such a vessel for a violation of U.S. law is impermissible under the Felonies Clause of the Constitution.”

From The Wall Street Journal • Dec. 8, 2025

That is just flat-out impermissible under the law as it stood on Thursday.

From Slate • Dec. 5, 2025

Supreme Court announced its decision: Life imprisonment without parole sentences imposed on children convicted of non-homicide crimes is cruel and unusual punishment and constitutionally impermissible.

From "Just Mercy" by Bryan Stevenson