a chemical substance derivable from a mold or bacterium that kills microorganisms and cures infections; "when antibiotics were first discovered they were called wonder drugs"
threatening or foreshadowing evil or tragic developments; "a baleful look"; "forbidding thunderclouds"; "his tone became menacing"; "ominous rumblings of discontent"; "sinister storm clouds"; "a sinister smile"; "his threatening behavior"; "ugly black clouds"; "the situation became ugly"
deadly or sinister; "the Florida eagles have a fierce baleful look"