dun vs halcyon

dun

noun
  • A fly made to resemble the mayfly subimago. 

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

  • 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. 

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

adj
  • Of a brownish grey colour. 

halcyon

noun
  • The dead body of such a bird, said in Tudor times to act as a weather vane when hung from a beam. 

  • A kingfisher whose nesting by the sea was said, in classical mythology, to cause the Gods to restrain the wind and waves. 

  • A tropical kingfisher of the genus Halcyon, such as the sacred kingfisher (Halcyon sancta) of Australia. 

adj
  • Pertaining to the halcyon or kingfisher. 

  • Calm, undisturbed, peaceful, serene. 

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