clench vs hippus

clench

verb
  • To close tightly. 

  • To grip or hold fast. 

noun
  • A tight grip. 

  • A local chapter of the Church of the SubGenius parody religion. 

  • A seal that is applied to formed thin-wall bushings. 

hippus

noun
  • pupillary athetosis; spasmodic dilation and contraction of the pupil between the sphincter and dilator muscles. 

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