Where does “Doolish” come from?

Doolish (Manx) comes from Manx doo, from Old Irish dub, from Proto-Celtic dubus, from Proto-Indo-European dʰewbʰ-, from Proto-Indo-European dʰewh₂- — smoke; mist, haze.

Ancestry of “Doolish”, step by step

Doolish traces back through two separate lines of ancestry.

via Manx doo

StepLanguageWordMeaning
1Manxdooblack; inky; ink
2Old Irishdubblack; morally dark, dire, gloomy, melancholy;...
3Proto-Celticdubusblack
4Proto-Indo-Europeandʰewbʰ-deep
5Proto-Indo-Europeandʰewh₂-smoke; mist, haze

via Manx glish

StepLanguageWordMeaning
1Manxglish
Every word from Proto-Indo-European dʰewh₂-Every word from Proto-Indo-European dʰewbʰ-Every word from Proto-Celtic dubus