Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
supplōsĭo (subpl-), and supplau-sĭo (subpl-), ōnis, f. [supplodo], a stamping with the feet: pedis, Cic. de Or. 3, 12, 47; 3, 59, 220; id. Brut. 38, 141; 80, 278; Auct. Her. 3, 15, 27; Quint. 10, 7, 26; 11, 3, 128.