not acceptable; not welcome; "a word unacceptable in polite society"; "an unacceptable violation of personal freedom"
not adequate to give satisfaction; "the coach told his players that defeat was unacceptable"
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'"
without a basis in reason or fact; "baseless gossip"; "the allegations proved groundless"; "idle fears"; "unfounded suspicions"; "unwarranted jealousy"