Garbled text that is the result of bytes being decoded using an incorrect coding.
Mojibake is the phenomenon which occurs when text is decoded from a byte stream using the wrong character encoding, resulting in a sequence of characters which is unreadable. The term "mojibake" is derived from Japanese where it literally means "unintelligible sequence of characters".
Example mojibake:
اÙ"إعÙ"ان اÙ"عاÙ"Ù