Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
au, interj., v. 2. hau.
1. hau (also au), interj., an exclamation of pain or grief, Oh! ah! au, nullan tibi lingua’st? Plaut. Stich. 1, 3, 104; id. Cist. 3, 15; Ter. And. 4, 4, 12; 42; id. Eun. 4, 3, 14; id. Heaut. 5, 3, 13; id. Ad. 3, 2, 38; id. Phorm. 5, 1, 27 et saep.