unimportant UK /ˌʌnɪmˈpɔːtənt/US /ˌʌnɪmˈpɔɹtənt/ adjective1 •petty; not important or noteworthyIt’s to the credit of this remarkable writer that those absences seem unimportant beside what is so rousingly present. — 2009 formsmore unimportant · most unimportant