Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
suffōcātĭo (subf-), ōnis, f. [suffoco], a choking, stifling, suffocating, Sen. Ep. 54, 2; hence, mulierum, suffocation of the womb, hysterical passion, Plin. 20, 5, 15, § 30; 26, 15, 90, § 158; v. suffoco, I.