Thank you, Grayhead, for starting my Friday off with a rollicking laugh. I can tell it's going to be a great weekend!
Allow me to elucidate you and your friends listed in the "Like" box on modern culture. Urban Dictionary is NOT the source you should necessarily be using when searching for the proper use of words and terms. Wikipedia describes Urban Dictionary as "a crowdsourced online dictionary . . . intended as a dictionary of slang, or cultural words or phrases, not typically found in standard dictionaries" In other words, it could have been some middle-aged housewife in Kansas or a nine-year-old go-getter from the suburbs, or possibly our very own dadika13 (rather than Samuel Johnson or Noah Webster) who decided one day to submit their made-up word to the Urban Dictionary archives. Don't trust everything you read on the Internet, and as I've said before, come correct when you come a'correctin'.
And now, here's a link for you:
https://www.merriam-webster.com/dictionary/wack