Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
sēdātĭo, ōnis, f. [sedo, II.], an allaying, assuaging, calming of the passions (Ciceron.): perturbationum animi, Cic. Off. 1, 27, 93: maerendi, id. Tusc. 3, 27, 65: aegritudinis, id. ib. 4, 29, 63: animi, id. Fin. 1, 19, 64.