/ Dictionary / Index D defection: Meaning and Definition of Find definitions for: de•fec•tion Pronunciation: (di-fek'shun), [key] — n. desertion from allegiance, loyalty, duty, or the like; apostasy: His defection to East Germany was regarded as treasonable. failure; lack; loss: He was overcome by a sudden defection of courage. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: defection (Thesaurus) defect defective Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language