Underwater (adjective)

1. Lying or situated below the surface of the water.
2. Relating to or used in activities or operations beneath the surface of water.

Origin:

Mid 17th century: from under- + water.

Examples:

1. She loved swimming in the ocean and discovering the beauty of the underwater world.
2. The wreckage of the ship was found underwater.
3. Underwater photography is a challenging but rewarding hobby.
4. The submarine is equipped for underwater exploration and research.
5. The resort offered scuba diving and other underwater activities for guests.