Correct spelling for the English word "blass" is [blˈas], [blˈas], [b_l_ˈa_s] (IPA phonetic alphabet).
The word "blass" is of German origin. It comes from the Old High German word "blass", which means "pale" or "colorless". This German word can be traced back further to the Old Saxon word "blāt", which has a similar meaning. Over time, "blass" has been adopted into many languages, including English, where it retains its meaning of referring to a lack of color or paleness.