Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
palpus, i, m. (nom. not in use) [1. palpo], the soft palm of the hand (Plautin.): timidam palpo percutit, Plaut. Am. 1, 3, 28: palpo percutis, id. Merc. 1, 2, 42: mi obtrudere non potes palpum, id. Ps. 4, 1, 35.