Lewis & Short

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.