shackle vs throttle

shackle

noun
  • A U-shaped piece of metal secured with a pin or bolt across the opening, or a hinged metal loop secured with a quick-release locking pin mechanism. 

  • A link for connecting railroad cars; a drawlink or draglink. 

  • A restraint on one's action, activity, or progress. 

  • A length of cable or chain equal to 12+¹⁄₂ fathoms or 75 feet, or later to 15 fathoms. 

  • A fetter-like band worn as an ornament. 

  • A restraint fit over a human or animal appendage, such as a wrist, ankle or finger; normally used in pairs joined by a chain. 

verb
  • To render immobile or incapable; to inhibit the progress or abilities of. 

  • To shake, rattle. 

  • To restrain using shackles; to place in shackles. 

throttle

noun
  • The lever or pedal that controls this valve. 

  • A valve that regulates the supply of fuel-air mixture to an internal combustion engine and thus controls its speed; a similar valve that controls the air supply to an engine. 

verb
  • To utter with breaks and interruption, in the manner of a person half suffocated. 

  • To have the throat obstructed so as to be in danger of suffocation; to choke; to suffocate. 

  • To control or adjust the speed of (an engine). 

  • To breathe hard, as when nearly suffocated. 

  • To cut back on the speed of (an engine, person, organization, network connection, etc.). 

  • To strangle or choke someone. 

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