/ Dictionary / Index S semiplastic: Meaning and Definition of Find definitions for: sem•i•plas•tic Pronunciation: (sem"ē-plas'tik, sem"ī-), [key] — adj. imperfectly plastic; in a state between rigidity and plasticity. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. semipermeable semipolitical 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