attrition (n.) Look up attrition at Dictionary.com
1540s, "abrasion, a scraping," from Latin attritionem (nominative attritio), literally "a rubbing against," noun of action from past participle stem of atterere "to wear, rub away," figuratively "to destroy, waste," from ad "to" (see ad-) + terere "to rub" (see throw (v.)). The earliest sense in English is from Scholastic theology (late 14c.), "sorrow for sin merely out of fear of punishment," a minor irritation, and thus less than contrition. The sense of "wearing down of military strength" is a World War I coinage (1914). Figurative use by 1930.