Wikipedia
Dúrnir was a dwarf who appears in three Old Norse skaldic poems, which suggests that he once was a well-known dwarf in Norse mythology.
The most notable poem is Ynglingatal:
En dagskjarr Dúrnis niðja salvörðuðr Sveigði vétti, þá er í stein enn stórgeði Dusla konr ept dvergi hljóp, ok salr bjartr þeira Sökmímis jötunbyggðr við jöfri gein. By Diurnir's elfin race, Who haunt the cliffs and shun day's face, The valiant Swegde was deceived, The elf's false words the king believed. The dauntless hero rushing on, Passed through the yawning mouth of stone: It yawnedit shutthe hero fell, In Saekmime's hall, where giants dwell.A more literal translation:
The day-fearing spawn of Durnir warden of the hall betrayed Sveigdir who into stone the rash hero ran after the dwarf. The bright hall of Soekmimir built of giants was enriched by the chieftain`s presence.He also appears in a list of Dwarves in the anonymous Dverga heiti:
Alþjófr, austri, aurvangr ok dúfr, ái, andvari, ónn ok draupnir, dori ok dagfinnr, dulinn ok ónarr, alfr ok dellingr, óinn ok durnir.The third poem is found in Laufás-Edda:
Kveða skal hróðr fyr hríðar hræ-blakks viðum sævar, drykkr var Durnis rekkum døkkr, ljósara nøkkvi.Snorri also includes Dúrnir in a list of giants in the Skáldskaparmál section of his Prose Edda (Faulkes translation, p. 157).
It is possible that the name Durnir is an emendation (or a case variety) of Durinn, mentioned as the father of dvarfs in Dvergatal. Both names mean door, or door-warden. The names Durinn og Durnir do not appear in the same texts. The Norwegian translation of Ynglinga Saga from 1900 uses the name of Durinn instead of Durnir.