/ Dictionary / Index U underarm: Meaning and Definition of Find definitions for: un•der•arm Pronunciation: (un'dur-ärm"), [key] — adj. of, situated, or for use under the arm or in the armpit: an underarm deodorant. underhand: an underarm pitch in softball. —n. armpit. —adv. underhand. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: underarm (Thesaurus) underage underarmed Related Content Daily Word Quiz: fidelity Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language