Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
pervĭam, adv. [per-via], accessible (cf. pervius; ante-class. and post-Aug.): angulos aedium perviam facitis, i. q. pervios, Plaut. Aul. 3, 2, 24; Front. Orat. 1 fin. Mai: divus Augustus reprehendens Ti. Claudium ita loquitur: Scribis enim perviam ἀντὶ τοῦ obviam, Charis. p. 187 P.