Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
succĭnum, i, v. sucinum.
sūcĭnum (succ-), i, n. [sucus], amber, usu. called electrum, Plin. 37, 2, 11, § 30; Mart. 3, 65, 5; 5, 37, 11; Juv. 6, 573 al.