Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
pŏpīno, ōnis, m. [popina], a frequenter of eating-houses, a gormandizer, Lucil. and Varr. ap. Non. 161, 16 sq.; Hor. S. 2, 7, 39; Suet. Gram. 15.