from
The Collaborative International Dictionary of English v.0.48
Bob \Bob\, v. i.
1. To have a short, jerking motion; to play to and fro, or up
and down; to play loosely against anything. "Bobbing and
courtesying." --Thackeray.
[1913 Webster]
2. To angle with a bob. See {Bob}, n., 2 & 3.
[1913 Webster]
He ne'er had learned the art to bob
For anything but eels. --Saxe.
[1913 Webster]
{To bob at an apple}, {cherry}, etc. to attempt to bite or
seize with the mouth an apple, cherry, or other round
fruit, while it is swinging from a string or floating in a
tug of water.
[1913 Webster]