Infernal (adjective)

Relating to or characteristic of hell; very unpleasant or painful.

Origin:

Late 16th century: from latin infernus "lower" (as in the underworld), from inferus "below".

Examples:

1. The infernal heat of the desert was unbearable.
2. The infernal noise was driving her insane.
3. The infernal pain was more than she could handle.
4. The infernal conditions made it impossible to continue.
5. The infernal machine was causing more problems than it solved.