doff vs shale

doff

verb
  • To remove or take off (something such as clothing). 

  • To get rid of, to throw off. 

  • To remove or tip a hat, as in greeting, salutation or as a mark of respect. 

  • To strip; to divest; to undress. 

shale

verb
  • To take off the shell or coat of. 

noun
  • A shell or husk; a cod or pod. 

  • A fine-grained sedimentary rock of a thin, laminated, and often friable, structure. 

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