boak vs keck

boak

verb

  • To retch or vomit. 

keck

verb

  • To heave or retch as if to vomit. 

noun

  • animal dung 

  • The cow parsley (Anthriscus sylvestris). 

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