bobbing

Example:The old man was bobbing up and down on the front porch, rocking back and forth.

Definition:moving between two higher and lower points, often repeatedly

Example:His support for the project bobbed on and off depending on his mood.

Definition:to happen or be present at intervals rather than continuously

Example:The little boat bobbed in the water, making it difficult to catch the fish.

Definition:being partially or wholly submerged in water

Example:The sailor bobbed with the waves of the sea, keeping his balance on the deck.

Definition:moving in a manner that follows the movement of waves

Example:She bobbed back and forth in front of the mirror, trying to decide on the best hairstyle.

Definition:moving in one direction and then returning to the original position