clonus vs pang

clonus

noun
  • A muscular spasm with regular contractions. 

pang

noun
  • A paroxysm of extreme physical pain or anguish; a feeling of sudden and transitory agony; a throe. 

  • A sudden sharp feeling of an emotional or mental nature, as of joy or sorrow. 

verb
  • To cause to have great pain or suffering; to torment, to torture. 

  • simple past tense of ping 

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