What is the origin of toplofty?

Toplofty, “condescending; haughty,” is a back formation of earlier toploftical, of similar meaning. Both adjectives are humorous colloquialisms. The underlying phrase is top loft, “the uppermost story, topmost gallery.” Toploftical appears, sort of, in everyone’s favorite bedtime reading, Finnegans Wake (1939): “…celescalating the himals and all, hierarchitectitiptitoploftical, with a burning bush abob off its baubletop…” Toplofty entered English in the first half of the 19th century.