Definitions:

1. not adequate to give satisfaction adjective
   • The coach told their players that defeat was unacceptable.
2. not conforming to standard usage adjective
   • the following use of `access' was judged unacceptable by a panel of linguists

Synonyms:

• impossible
• insufferable
• unaccepted
• unashamed
• unsufferable

NearBy Words:

• unacceptableness