/ Dictionary / Index S sunproof: Meaning and Definition of Find definitions for: sun•proof Pronunciation: (sun'prf"), [key] — adj. impervious to sunlight or damage by the rays of the sun. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Sun Prairie sun protection factor Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language