Today's Word of the Day means...
[money sense probably fr the expression hard Jackson or hard Jackson money, referring to President Andrew Jackson and found by 1838; first verb sense perhaps related to mid-1800s British criminal slang jack, ''run away, escape,'' or perhaps by folk etymology fr jank, an echoic companion of jink; compare jink-jank with yin-yang and zig-zag; stealing sense probably fr hijack and related to carjacking]
Man; friend; fellow; mac •Used in addressing any man, whatever his name: Man, he's murder, Jack/ That supposed to be funny, jack? (1889+)
Nothing at all, zero; nada; jack shit: You don't know jack squat about going to college these days