Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
suf-frīgĭdus (subf-), a, um, adj., rather cold or frigid (post-class. and very rare); trop.: argumentum, Amm. 17, 11, 4.
Adv.: suffrīgĭdē, rather coldly or frigidly: nimis minute ac prope etiam suffrigide, Gell. 2, 9, 4.