fishtail vs librate

fishtail

verb
  • To move with the tail swinging from side to side in this way. 

  • To swing the back of a vehicle (originally an aircraft) from side to side. 

  • To cause the back of (a vehicle) to swing from side to side. 

noun
  • The skidding of the back of a vehicle from side to side. 

  • A kind of chisel with a flared blade. 

  • The tail of a fish, or an object resembling this. 

librate

verb
  • To oscillate (like the beam of a balance). 

  • To be poised; to balance oneself. 

noun
  • A piece of land having a value of one pound per year. 

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