Bob
.To give the bob to any one. To deceive, to balk. This word is a corruption of pop. The bob of a pendulum or mason’s plumb-line is the weight that pops backwards and forwards. The bob of a fishing-line pops up and down when fish nibble at the bait. To bob for apples or cherries is to try and catch them while they swing backwards and forwards. As this is very deceptive, it is easy to see how the word signifies to balk, etc.
To bob means also to thump, and a bob is a blow.