Grievous means causing severe pain, suffering, or sorrow. When something is grievous, it's deeply serious and harmful, involving real damage or profound distress.

A grievous injury in sports isn't a scraped knee but something severe like a broken bone that requires surgery. A grievous mistake isn't forgetting your homework but doing something that causes real harm to yourself or others, like betraying a close friend's trust. When someone suffers a grievous loss, like losing a loved one, they experience profound sadness that affects them deeply.

The word carries weight and gravity. You wouldn't describe a minor inconvenience as grievous. It's reserved for truly serious matters. A teacher might say a student made a grievous error in judgment if they did something that hurt others, not if they simply got an answer wrong on a test.

Grievous describes things that cause or deserve genuine anguish. In older texts and formal speech, you might also see the related word aggrieved, which describes someone who feels they've been treated unfairly or harmed. When something is grievous, it demands to be taken seriously.