Entry 1 sense Webster, 1913 Unusual /ən-yo͞ozh'-o͞oˌ-əl/ · Un·u·su·al · IPA /ʌnˈjuːʒ(u)əl/ 01 a. Not usual; uncommon; rare; as, an unusual season; a person of unusual grace or erudition. 1. Not usual; uncommon; rare; as, an unusual season; a person of unusual grace or erudition.