Bob1  —v. (-bb-) 1 move quickly up and down. 2 (usu. Foll. By back, up) bounce or emerge buoyantly or suddenly. 3 cut (the hair) in a bob. 4 curtsy. —n. 1 jerking or bouncing movement, esp. Upward. 2 hairstyle with the hair hanging evenly above the shoulders. 3 weight on a pendulum etc. 4 horse's docked tail. 5 curtsy. [imitative]