dun vs horseflesh

dun

adj
  • Of a brownish grey colour. 

intj
  • Imitating a deep bass note, such as that found in suspenseful music. 

noun
  • A collector of debts, especially one who is insistent and demanding. 

  • A fly made to resemble the mayfly subimago. 

  • A newly hatched, immature mayfly; a mayfly subimago. 

  • An ancient or medieval fortification; especially a hill-fort in Scotland or Ireland. 

  • A mound or small hill. 

  • A brownish grey colour. 

  • An urgent request or demand of payment. 

  • A structure in the Orkney or Shetland islands or in Scotland consisting of a roundhouse surrounded by a circular wall; a broch. 

verb
  • To harass by continually repeating e.g. a request. 

  • To ask or beset a debtor for payment. 

horseflesh

adj
  • Of the colour of horseflesh; of a peculiar reddish-brown hue. 

noun
  • Horses collectively, with reference to driving, riding, or racing. 

  • A species of Bahama mahogany, Lysiloma sabicu and Lysiloma latisiliquum. 

  • The flesh of a horse; horsemeat. 

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