pentyrru marwor am ben rhywun

• pentyrru marwor ar ben rhywun

From the Bible, Romans 12:20, see quotation.

pentyrru marwor am ben rhywun (first-person singular present pentyrraf marwor am ben rhywun)

1. (idiomatic) to heap coals of fire on someone's head, to provoke someone to remorse with good deeds

• 1588, William Morgan, transl., Y Beibl : Y Beibl cyssegr-lan, 1st edition, London: Humphrey Toy, Epiſtol Paul yr Apoſtol at y Rʜᴠꜰᴇɪɴɪᴀɪᴅ 12:20:

  Am hynny os dy elyn a newyna, portha ef: os ſycheda, dod iddo ddiod, canys os gwnei hyn ti a bentyrri farwor am ei ben ef.

  Therefore if thine enemy hunger, feed him; if he thirst, give him drink: for in so doing thou shalt heap coals of fire on his head.

• R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke et al., editors (1950–present), “pentyrru marwor”, in Geiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies