Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
truncŭlus, i, m. dim. [1. truncus], a small piece cut off from the body, a bit, tip: suum, pigs’ trotters, pettitoes, Cels. 2, 20; 2, 22; 4, 7 fin.