An open handed, back-hand slap to the temple. Not intended to knock someone out, but instead, to make someone appreciate your point of view in a forceful manner so they eventually agree with you. This is considered a more intimidating and more painful form of "Point Making" as opposed to the more traditional and less painful open hand cheek slap.
Jeff: Hey Greg, Jimmy owes me some money and I asked him to pay me and he laughed.
Greg: He laughed?
Jeff: Yes, he laughed!
Greg: You need to Jack-Smack him and let him know you are serious without knocking him out.
Greg: He laughed?
Jeff: Yes, he laughed!
Greg: You need to Jack-Smack him and let him know you are serious without knocking him out.
by Norge August 12, 2010
When someone takes an unnecessarily long hit off someone’s vape or cart and taxes it, often killing it in the one lung destroying hit they take.
by Coochie catcher May 5, 2019
Not having or doing anything
"Do you have money? I don't have jack smack"
"What did you do last weekend? I didn't do jack smack!"
"What did you do last weekend? I didn't do jack smack!"
by SuperThought October 2, 2003
by J.olson27 February 2, 2021