inkle vs let know

inkle

verb
  • To hint at; disclose. 

  • To have a hint or inkling of; divine. 

noun
  • Narrow linen tape, used for trimmings or to make shoelaces 

let know

verb
  • To inform (someone) (of something). 

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