"to strike sharply," 1719, probably of imitative origin. The noun is from 1737. The word in out of whack (1885) is perhaps the slang meaning "share, just portion" (1785), which may be from the notion of the blow that divides, or the rap of the auctioneer's hammer.
tv. to complete something easily or quickly. : If you want a pair of these, I can whack them off for you in a few minutes.
tv. to cut or chop something off. : A tree branch is rubbing against the house. I guess I'll go out and whack that branch off.
Dictionary of American Slang and Colloquial Expressions by Richard A. Spears.Fourth Edition. Copyright 2007. Published by McGraw Hill.
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