(adv.) Primarily; originally; essentially; radically; at the foundation; in origin or constituents.

a outrance absolutely all out at bottom at heart at the core au fond basically beyond all bounds beyond compare beyond comparison beyond measure completely dead downright essentially extremely flat out immeasurably in essence in itself in substance in the extreme in the main incalculably indefinitely infinitely materially most per se perfectly primarily purely radically substantially totally unconditionally unequivocally utterly with a vengeance