Encourage Baby To Embrace Their Dark Side With This Striking Irish Name. Dwain Means "dark" Or "swarthy," And Is An Alternative Version Of Duane And Dwayne, With Duane Originally Being An Irish Surname. This Boys Name Comes From The Irish Word dubh, Which Means "black." With Dwain, You Can Pay Homage To Any Irish Heritage With A Name That Feels Both Familiar As Well As Unusual.