WordWeb Online

1. Not adequate to give satisfaction
   "the coach told his players that defeat was unacceptable"
    
2. Not acceptable; not welcome
   "a word unacceptable in polite society"; "an unacceptable violation of personal freedom"
    
3. (of a person) very annoying or difficult to deal with
   "unacceptable behaviour"
   - impossible, insufferable, unsufferable
    
4. Not conforming to standard usage
   "the following use of 'access' was judged unacceptable by a panel of linguists; 'You can access your cash at any of 300 automatic tellers'"
   - unaccepted

See also: exceptionable, intolerable, nonstandard, objectionable, unacceptableness, unbearable, unendurable, unsatisfactory, unwelcome

Antonym: acceptable

Encyclopedia: Unacceptable