adjective

1. Obsolete foreign or alien; in the ancient world, non-Greek, non-Roman, or non-Christian
2. characterized by substandard usages in speaking or writing
3. characteristic of barbarians; primitive or lacking in civilization
4. uncultured, crude, coarse, rough, etc.
5. cruel; brutal
6. harsh in sound; raucous

Etymology: L barbarus < Gr barbaros, foreign, strange, ignorant < IE echoic base *barbar-, used for unintelligible speech of foreigners > Sans barbara-, stammering, non-Aryan