Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
hŏmĭcīdĭum, ĭi, n. [homicida], manslaughter, homicide, murder (post-class.): si quis homicidii accusetur, Quint. 3, 10, 1; 4, 2, 52; 11, 3, 59; Petr. 137; Plin. 18, 3, 3, § 12; Tac. G. 21.