Yahoo was talking about How did the phrase “out of whack” come about? and they mentioned that the phrase “in fine whack” had previously been used to describe something fit and sturdy. As John Hale describes Abraham Lincoln in 1863:
“The Tycoon is in fine whack. I have rarely seen him more serene and busy. He is managing this war, the draft, foreign relations, and planning a reconstruction of the Union, all at once.”
So next time someone says you are a wack-o, say thanks!