/ Dictionary / Index S substitutive: Meaning and Definition of Find definitions for: sub•sti•tu•tive Pronunciation: (sub'sti-t"tiv, -ty"-), [key] — adj. serving as or capable of serving as a substitute. pertaining to or involving substitution. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. substitution reaction substrate 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