Grievous (adjective)

1. Very serious and causing great distress or worry.
2. Causing or capable of causing harm or death.
3. Extremely bad or serious.

Origin:

Middle english grevous, from old french grieu, from latin gravis "heavy, serious".

Examples:

1. The accident was a grievous blow to the whole family.
2. The loss of life in the war was a grievous one.
3. The judge considered the crime to be a very grievous one.
4. The injury was so severe that it was considered a grievous harm.
5. The situation was so bad that it was considered a grievous injustice.