/ Dictionary / Index S sin tax: Meaning and Definition of Find definitions for: sin' tax" Pronunciation: [key] — Informal. Informal. a tax levied on cigarettes, liquor, gambling, or other things considered neither luxuries nor necessities. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. sinsyne sinter Related Content Daily Word Quiz: endear Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language