Unintelligible means impossible to understand or make sense of. When something is unintelligible, you can hear it or see it, but you cannot figure out what it means.

Imagine your little brother mumbling with his mouth full of food. You can hear sounds coming out, but the words are completely unintelligible. Or picture trying to read a doctor's messy handwriting: the letters are there, but they're so poorly formed that the prescription becomes unintelligible.

The word often describes speech that's garbled, muffled, or delivered in a language you don't know. When a character in a movie speaks through a broken radio with static interference, their message becomes unintelligible. Sometimes people speak too quickly, too quietly, or with such a strong accent that their words turn unintelligible to listeners.

Writing can be unintelligible too. A paragraph with no punctuation, random words, and broken grammar might be technically readable but still unintelligible because it makes no sense. The key is that something unintelligible exists and reaches you, but your brain cannot decode it into meaning. It's the opposite of clear or comprehensible.