1. To be a weight or pressure on; be heavy on.
The pack weighed heavily on the soldier's back.
2. To make sad or worried; trouble; disturb; upset.
Sadness weighed on Mary's heart when her kitten died.
John's wrongdoing weighed upon his conscience.
The teacher's advice weighed upon Tom's mind.
3. To be a burden to.
His guilt weighed heavily upon him.