Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Trōĭlus, i, m., = Τρώϊλος, a son of Priam, slain by Achilles, Verg. A. 1, 474; Plaut. Bacch. 4, 9, 30; 4, 9, 36; Hor. C. 2, 9, 16; Dict. Cret. 4, 9.