cowp vs keel over

cowp

verb
  • To fall or tip over. 

noun
  • A filthy and disgusting place. 

  • A reversal of fortune; An unexpected misfortune. 

keel over

verb
  • To collapse in a faint; to black out, to swoon. 

  • To die. 

  • Of a vessel: to roll so far on its side that it cannot recover; to capsize or turn turtle. 

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