Where does “dúchroíoch” come from?

dúchroíoch (Irish) comes from Irish dú-, from Irish dubh, from Old Irish dub, from Proto-Celtic dubus, from Proto-Indo-European dʰewbʰ-, from Proto-Indo-European dʰewh₂- — smoke; mist, haze.

dúchroíoch (Irish): joyless, melancholic; black-hearted, spiteful

Definitions

joyless, melancholic; black-hearted, spiteful

Ancestry of “dúchroíoch”, step by step

Step	Language	Word	Meaning
1	Irish	dú-	black, dark; great, intense; evil
2	Irish	dubh	black; black-haired
3	Old Irish	dub	black; morally dark, dire, gloomy, melancholy;...
4	Proto-Celtic	dubus	black
5	Proto-Indo-European	dʰewbʰ-	deep
6	Proto-Indo-European	dʰewh₂-	smoke; mist, haze

Every word from Proto-Indo-European dʰewh₂- →Every word from Proto-Indo-European dʰewbʰ- →Every word from Proto-Celtic dubus →