Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ēheu, interj., an interjection of pain or grief, ah! alas! Plaut. Capt. 1, 2, 49; 5, 3, 18; id. Trin. 2, 4, 102; id. Mil. 4, 8, 32 al.; Ter. Heaut. 1, 1, 31; id. Hec. 1, 1, 17; id. Phorm. 1, 4, 10.
Often followed by quam: eheu, quam ego nunc totus displiceo mihi, Ter. Heaut. 5, 4, 20; Hor. S. 1, 3, 66. (The epic and lyric poets have everywhere ēheu; and hence many moderns, partly in accordance with better MSS., read everywhere heu heu; cf. Burmann, Voss, Wagner, and Ribbeck, Verg. E. 2, 58; also Forbig. ad loc.; Hand Turs. 2, 358 sq.; Sillig Cat. p. 283; Huschk. Tib. II. p. 711; Fea and Keller, Hor. C. 1, 15, 9; but in ib. 1, 35, 33, and 2, 14, 1 al. the best editions have ēheu.)