Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
* bĭsulcĭlingua, ae, adj. [bisulcuslingua], with a cloven tongue; trop., of a hypocrite, a double-tongued, deceitful person: bisulcilingua, quasi proserpens bestia, Plaut. Poen. 5, 2, 74.