Unbearable (adjective)

1. Unable to be endured; too painful or unpleasant to be tolerated.
2. Extremely bad or unpleasant.

Origin:

Late middle english (in the sense "impossible to bear"): from un- "not" + bearable.

Examples:

1. The heat was unbearable and we decided to go inside.
2. The noise was unbearable and we had to leave the concert.
3. The pain was unbearable and I had to take some painkillers.
4. The tension in the room was unbearable and everyone was on edge.
5. The smell was unbearable and we had to open the windows.