/ Dictionary / Index I infinitival: Meaning and Definition of Find definitions for: in•fin•i•ti•val Pronunciation: (in"fin-i-tī'vul), [key] — adj. Gram. of or pertaining to the infinitive. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: infinitival (Thesaurus) infinitesimal calculus infinitive Related Content Daily Word Quiz: sequester Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language