Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
prae-prŏpĕrus, a, um, adj., too quick or hasty, over-hasty, sudden, precipitate (class.): praepropera festinatio, Cic. Fam. 7, 8, 1: prensatio, id. Att. 1, 1, 1: celeritas, Liv. 31, 42: ingenium, rash, id. 22, 41: nisus, Sil. 15, 757: amor, Val. Max. 6, 3, 6.
Hence, adv.: praeprŏpĕrē, very quickly, very hastily, with over-haste (rare; not in Cic. or Cæs.): peri praepropere, Plaut. Mil. 2, 4, 10 (v. Ritschl ad h. l.): festinans praepropere, Liv. 37, 23, 10: raptim omnia praepropere agendo, id. 22, 19, 10; Quint. 12, 6, 2; Suet. Oth. 8.