Blow

blō, n. a stroke or knock: a sudden misfortune or calamity.— At a blow , by a single action, suddenly; To come to blows , To exchange blows , to come to hostilities; Without striking a blow , without a struggle. [A.S. bléowan is doubtful, cog. with Dut. blouwen , to dre (beat) flax, Ger. blāuen , to beat hard. The noun appears in the 15th century without evidence of parentage.]