obdurate

When you are confronted with someone obdurate, you may end up feeling dour. During the encounter, you may find that you need to be durable to keep your sanity intact. Maybe you will find such situations less stressful in the future if you can face them knowing that the words obdurate, dour, during, and durable are etymological cousins. All of those words trace back to the Latin adjective durus, which means "hard." A form of this adjective can still be found in dura mater, the name for the tough fibrous material that surrounds the brain and spinal cord; it comes from a Medieval Latin phrase meaning, literally, "hard mother."