Monstrous (adjective)

1. Unusually large and ugly or terrifying.
2. Extremely wicked or cruel.

Origin:

Middle english: from old french monstreux, from latin monstruosus, from monstrum "monster".

Examples:

1. The monster was a monstrous creature.
2. The storm was a monstrous weather event.
3. The crime was a monstrous act of violence.
4. The mistake was a monstrous error.
5. The greed was a monstrous appetite.