Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
praeter-ăgo, no perf., actum, 3, v. a., to drive by or past (poet. and post-class.): deversoria nota Praeteragendus (est) equus, Hor. Ep. 1, 15, 10; Jul. Val. Rer. Gest. Alex. M. 1, 3.