Definition of "Unacceptable" :

adjective: not acceptable; not welcome

"A word unacceptable in polite society."

adjective: not adequate to give satisfaction

"The coach told his players that defeat was unacceptable."

adjective: 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'."

adjective: (used of persons or their behavior) not acceptable or reasonable