两败俱伤

both sides suffer (idiom) / neither side wins

two / both / some / a few / tael, unit of weight equal to 50 grams (modern) or 1⁄16 of a catty 斤[jin1] (old)

to defeat / to damage / to lose (to an opponent) / to fail / to wither

entirely / without exception / (literary) to be together / to be alike

(literary) all; both; entirely; without exception / (literary) to be together / (literary) to be alike

to injure / injury / wound