adj. & n.
adj. (fattier, fattiest) 1 like fat; oily, greasy. 2 consisting of or containing fat; adipose. 3 marked by abnormal deposition of fat, esp. in fatty degeneration.
n. (pl. -ies) colloq. a fat person (esp. as a nickname). fatty acid Chem. any of a class of organic compounds consisting of a hydrocarbon chain and a terminal carboxyl group, esp. those occurring as constituents of lipids. fatty oil = fixed oil. fattily adv. fattiness n.