Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
sanguĭsūga, ae, f. [sanguis-sugo], a blood-sucker, leech (called also hirudo), Cels. 5, 27, 16; Plin. 8, 10, 10, § 29; 32, 10, 42, § 123; Vulg. Prov. 30, 15.