Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
dissuāsĭo, ōnis, f. [dissuadeo], an advising to the contrary; a dissuasion (very rare): rogationis ejus, * Cic. Clu. 51, 140; so opp. suasio, Auct. Her. 1, 2.
In plur., Sen. Ep. 94, 39.