I. To make harsh or bitter, to embitter; lit. and trop. (very rare): “gaudia,” Stat. Th. 12, 75: “mortem,” Val. Fl. 6, 655.— Hence in an extended sense,
II. To augment or aggravate any thing disagreeable (cf. acuo): “formidine crimen acerbat,” Verg. A. 11, 407: “nefas Eteoclis,” Stat. Th. 3, 214.