Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
per-pāco, āvi, ātum, 1, v. a., to quiet completely, reduce to quiet (i. q. perdomare): omnibus perpacatis, Liv. 36, 21: Brennos perpacavit, Flor. 4, 12, 4; Aur. Vict. Vir. Ill. 33.