bob vs slough shark

bob

noun
  • The docked tail of a horse. 

  • A small wheel, made of leather, with rounded edges, used in polishing spoons, etc. 

  • A working beam in a steam engine. 

  • An unspecified amount of money. 

  • A graphical element, resembling a hardware sprite, that can be blitted around the screen in large numbers. 

  • A particular style of ringing changes on bells. 

  • A bobsleigh. 

  • A blow; a shake or jog; a rap, as with the fist. 

  • Any of various hesperiid butterflies. 

  • A bobbing motion; a quick up and down movement. 

  • A curtsy. 

  • 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. 

  • The dangling mass of a pendulum or plumb line. 

  • A short line ending a stanza of a poem. 

  • A bobber (buoyant fishing device). 

  • The short runner of a sled. 

verb
  • To bobsleigh. 

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

  • To curtsy. 

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

  • 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. 

  • To cut (hair) into a bob haircut. 

  • To shorten by cutting; to dock; to crop. 

slough shark

noun
  • northern pike 

How often have the words bob and slough shark occurred in a corpus of books? (source: Google Ngram Viewer )