Deepen (verb)

1. To make something deeper.
2. To increase the intensity or seriousness of something.

Origin:

From old english dēopian, from proto-germanic *deupōną ("to deepen"), from proto-indo-european *dheub- ("deep").

Examples:

1. The river deepened as it flowed through the canyon.
2. The hole deepened as the workers drilled.
3. The relationship deepened as they spent more time together.
4. The crisis deepened as the situation worsened.
5. The understanding deepened as more information was gathered.