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