Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
per-terrĕo, ui, ĭtum, 2, v. a., to frighten or terrify thoroughly: aliquem, Ter. Eun. 5, 3, 13: alios magnitudine poenarum, Caes. B. G. 7, 4; 50: metu perterriti, Cic. Caecin. 10, 26: obstupefactus ac perterritus, id. Cat. 2, 7, 14: maleficii conscientiā perterritus, id. Clu. 13, 38: ossa mea perterrita sunt, Vulg. Job, 4, 14 (but the true read., Cic. Caecin. 13, 37, is proterritus).