Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
pĕr-hūmānĭter, adv., v. perhumanus fin.
pĕr-hūmānus, a, um, adj., very kind, very courteous, very polite (class.): sermo, Cic. Q. Fr. 2, 6, 1: epistula, id. Att. 16, 12.
Adv.: pĕrhūmānĭter, very kindly, very politely: scribere ad aliquem, Cic. Fam. 7, 8, 1.