Insufferable (adjective)

1. Unbearable; intolerable.
2. Impossible to endure.

Origin:

From latin insufferabilis, from in- ("not") + sufferabilis ("able to be endured, sufferabl.e")

Examples:

1. The heat was insufferable, and we couldn't stay outside for more than a few minutes.
2. He was insufferable, constantly boasting and showing off.
3. The noise was insufferable, and I had to leave the concert early.
4. The pain was insufferable, and he had to be taken to the hospital.
5. The conditions in the factory were insufferable, with poor ventilation and long hours.