1. Too horrible or shocking to be expressed in words. This is the most common meaning. For example: "The atrocities they witnessed were unspeakable."
2. Extremely wonderful or beautiful, beyond words. This meaning is less common but still valid. For example: "The view from the mountaintop was unspeakable."
3. Impossible to articulate or describe. This meaning is more about the difficulty of conveying something verbally. For example: "The joy she felt was unspeakable."
The meaning of "unspeakable" depends on the context of the sentence.