importantly UK /ɪmˈpɔː.tənt.li/US /ɪmˈpɔɹ.tənt.li/ adverb2 •In an important manner.Even sitting in a restaurant, the person on a cell phone seems importantly busy and on the move. — 2001 •as a point that matters very much, used to mark what is being saidMore importantly and closer to life, slangs help build an instant intimacy and informality. — 2021 formsmore importantly · most importantly