bob

To move gently and vertically, in either a single motion or repeatedly up and down, at or near the surface of a body of water, or similar medium.

The cork bobbed gently in the calm water.

The ball, which we had thought lost, suddenly bobbed up out of the water.

To move (something) as though it were bobbing in water.

I bobbed my head underwater and saw the goldfish.

bob one’s head

To move (something) as though it were bobbing in water.

She bobbed on his knob.

To curtsy.

To strike with a quick, light blow; to tap.

And if any man hapned, by longe sittynge, to slepe, or, by any other countenance, to shewe him selfe to be weary, he was sodaynly bobbed on the face by the seruantes of Nero, […]

Lo, lo, lo, lo, what modicums of wit he vtters, his euaſions haue eares thus long, I haue bobd his braine more then he has beate my bones.

A bobbing motion; a quick up and down movement.

a bob of the head

A curtsy.

A bobber (buoyant fishing device).

Or yellow bobs turn’d up before the plough / Are chiefest baits, with cork and lead enough.

Any of various hesperiid butterflies.

A bob haircut.

Any round object attached loosely to a flexible line, a rod, a body part etc., so that it may swing when hanging from it.

Ecod! I have got them. Here they are. My cousin Con's necklaces, bobs and all.

The dangling mass of a pendulum or plumb line.

The docked tail of a horse.

The short runner of a sled.