In intransitive terms the difference between bob and swing
is that
bob is 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 while
swing is to fluctuate or change.
In transitive terms the difference between bob and swing
is that
bob is to shorten by cutting; to dock; to crop while
swing is in dancing, to turn around in a small circle with one's partner, holding hands or arms.
In obsolete terms the difference between bob and swing
is that
bob is a jeer; a sharp jest or taunt while
swing is free course; unrestrained liberty.
In lang=en terms the difference between bob and swing
is that
bob is an unspecified amount of money while
swing is the genre of music associated with this dance style.
As a proper noun Bob
is a diminutive=Robert given name.