/ Dictionary / Index S suboptimal: Meaning and Definition of Find definitions for: sub•op•ti•mal Pronunciation: (sub-op'tu-mul), [key] — adj. being below an optimal level or standard. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. suboceanic suborbital Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language