Incomprehensible (adjective)

1. Impossible to understand; not able to be grasped by the mind.
2. Not able to be explained or made clear; not able to be comprehended.
3. Not able to be interpreted; not able to be understood.

Origin:

From the latin word "incomprehensibilis" meaning "impossible to understand".

Examples:

1. The lecture was incomprehensible to most of the students.
2. The instructions were incomprehensible and no one knew what to do.
3. The book was incomprehensible, full of jargon and technical terms.
4. The message was incomprehensible due to poor translation.
5. The concept was incomprehensible to most people, even experts in the field.