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.

Definitions of impermissible
  1. adjective
    not permitted
    impermissible behavior”
    forbidden, out, prohibited, proscribed, taboo, tabu, verboten
    excluded from use or mention
    unsuitable or forbidden as a topic of conversation
    forbidden to the touch
    intolerable, unbearable, unendurable
    incapable of being put up with
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    allowable, permissible
    that may be permitted especially as according to rule
    capable of being borne or endured
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  2. adjective
    not allowable
    not deserving to be admitted
Word Family