Entry 1 sense Webster, 1913 Illegible /ĭlˌ-ĕj'-əb-əl/ · Il·leg·i·ble · IPA /ɪˈlɛd͡ʒəbəl/ 01 a. Incapable of being read; not legible; as, illegible handwriting; an illegible inscription. 1. Incapable of being read; not legible; as, illegible handwriting; an illegible inscription.