dagger (n.) Look up dagger at Dictionary.com
late 14c., apparently from Old French dague "dagger," from Old Provençal dague or Italian daga, of uncertain origin; perhaps Celtic, perhaps from Vulgar Latin *daca "Dacian knife," from the Roman province in modern Romania. The ending is possibly the faintly pejorative -ard suffix. Attested earlier (1279) as a surname (Dagard, presumably "one who carried a dagger"). Middle Dutch dagge, Danish daggert, German Degen also are from French.