1. not adequate to give satisfaction

- the coach told his players that defeat was unacceptable

Similar word(s): unsatisfactory

2. not acceptable; not welcome

- a word unacceptable in polite society

- an unacceptable violation of personal freedom

Similar word(s): exceptionable, objectionable, unsatisfactory, unwelcome

3. (used of persons or their behavior) not acceptable or reasonable

Similar word(s): intolerable, unbearable, unendurable, impossible

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'

Similar word(s): nonstandard, unaccepted