unintelligible

/ˈʌnənˌtɛlədʒəbəl/

Something unintelligible is difficult to understand, either because the room is too noisy or because the unintelligible thing is too quiet or confusing.

We use our intelligence to understand things, and something intelligible is easy to understand. Therefore, unintelligible things are hard to understand. A coded message is unintelligible if you don't know the code. A whisper in a loud room is unintelligible. A weird sentence like "The waffles ran away from the Easter basket" is unintelligible because it doesn't make any sense. If you can't hear or understand something, it's unintelligible (and probably frustrating too).

Definitions of unintelligible

1. adjective

   not clearly understood or expressed
   synonyms: opaque

   incomprehensible, uncomprehensible

   difficult to understand
2. adjective

   poorly articulated or enunciated, or drowned by noise
   “unintelligible speech”

   synonyms:

   incomprehensible, uncomprehensible

   difficult to understand

   slurred, thick

   spoken as if with a thick tongue

   antonyms:

   intelligible

   well articulated or enunciated, and loud enough to be heard distinctly

   comprehendible, comprehensible

   capable of being comprehended or understood