Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
vah (fuller form vaha, Plaut. Cas. 4, 4, 25; Afran. ap. Charis. p. 187 P.), interj., = Gr. οὐά, οὐᾶ; an exclamation of astonishment, joy, anger, etc., ah! oh! vah! solus hic homo’st, qui sciat divinitus, Plaut. Curc. 2, 1, 33; 2, 3, 79; id. Trin. 5, 2, 13 (ante-class. and late Lat.); id. Most. 1, 3, 99: vah! Homo amicus nobis jam inde a puero, Ter. Ad. 3, 3, 86: vah consilium callidum! id. And. 3, 4, 10; cf.: cum dolentes dicimus heu! vel cum delectamur vah dicimus, Aug. Tract. in Joan. 51: vah! apage te a me, Plaut. Am. 2, 1, 32; Ter. Ad. 3, 2, 17; 4, 2, 39; id. Eun. 4, 5, 4: vah! perii! hoc malum integrascit, id. And. 4, 2, 5; id. Heaut. 2, 3, 12; Vulg. Job, 39, 25; id. Matt. 27, 40.