Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
* permānasco, ĕre, v. inch. n. [id.], to flow to; hence, trop., to penetrate to a place: ad aliquem permanascere, to penetrate to his ears, to reach his ears, Plaut. Trin. 1, 2, 118.