dun vs nag

dun

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

  • To ask or beset a debtor for payment. 

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. 

nag

verb
  • To bother or disturb persistently in any way. 

  • To bother with persistent thoughts or memories. 

  • Anyone would think that I nagged at you, Amanda! (From Amanda! by Robin Klein) 

  • a nagging pain in his left knee 

  • To repeatedly remind or complain to (someone) in an annoying way, often about insignificant or unnecessary matters. 

  • The notion that he forgot something nagged him the rest of the day. 

noun
  • Someone or something that nags. 

  • A persistent, bothersome thought or worry. 

  • An old, useless horse. 

  • A repeated complaint or reminder. 

  • A small horse; a pony. 

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