Sindarin 

Dagnir Glaurunga

noun. slayer of Glaurung

dag- (“slay”) + (n-)dîr (“man, adult male”, here: “doer”) + Glaurung (dragon-name) + a (Doriathrin genitive ending) #The mutation of dîr to nir might be explained by the Doriathrin origin of the name.

Sindarin [Tolkiendil] Group: Tolkiendil Compound Sindarin Names. Published by

túrin turambar dagnir glaurunga

Túrin Turambar, Glaurung’s Bane

Sindarin [S/226; SA/dagor; SI/Dagnir Glaurunga; UT/145; WJ/103; WJI/Dagnir Glaurunga] Group: Eldamo. Published by