/ Dictionary / Index S spear gun: Meaning and Definition of Find definitions for: spear' gun" Pronunciation: [key] a device for shooting a barbed missile under water, usually by means of gas under pressure, a strong rubber band, or a powerful spring. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. spear grass spearhead Related Content Daily Word Quiz: procrastinate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language