SBD en · NOUN Meanings (abbreviation, alt-of, informal, initialism) Initialism of silent but deadly (fart): inaudible but odorous flatulence. alt of silent but deadly Whether a cow passes gas loudly, also known as tearing beef, or demurely emits an SBD makes no difference. 2007 December 8, Mo Rocca, “Wait, Wait... Don't Tell Me”, in National Public Radio: Forms SpellingFeaturesLabelsSource SBDs Number=Plur lexicographic Hypernyms fart Synonyms feist