na-adjective, noun which may take the genitive case particle 'no'
meaningless; incomprehensible; nonsensical
Describes something whose meaning cannot be understood, or that seems absurd or cryptic. Often used as a strong negative comment.
His explanation was incomprehensible.
His explanation made no sense at all.
This email is full of nonsense.
He sent me a message that made no sense.
He sometimes says things that don't make any sense.
不可解 is a formal word for something logically impossible to understand, while 意味不明 is a more colloquial, broadly applicable way to say something makes no sense.
支離滅裂 describes speech or writing that is disjointed and incoherent, a stronger claim than 意味不明's simple 'doesn't make sense'.
でたらめ emphasizes randomness or irresponsibility in what's said or done, whereas 意味不明 just says the meaning can't be grasped.
意味不明 is a neutral, formal way to say something's meaning is unclear, whereas ちんぷんかんぷん is a colloquial, vivid expression for complete incomprehension.
明確 means clear and well-defined, the opposite of 意味不明's sense of being unclear or nonsensical.
意味深 shares the kanji 意味 with 意味不明 but means the opposite—full of suggestive, hidden meaning rather than lacking meaning.
Compound of 意味 (meaning) and 不明 (unclear, unknown). The combination straightforwardly yields 'meaning unclear'.