Old English scearn "dung, muck," from Proto-Germanic *skarnom- (cognates: Old Frisian skern, Old Norse skarn, Danish skarn), a past participle form from *sker- "to cut" (see shear). Compare Old English scearnbudda "dung beetle," and Scottish Sharnie "a name given to the person who cleans a cow-house" [Jamieson].