to beat with superior logic; to pwn with someone with their own argument
Man A: kim jung il is the leader of south korea
Man B: no he's not, he leads north korea Man A: prove it!
(Man B googles said issue, and is proven correct)
Man C: man, he just used his logictify!
To take something small, that doesn't quite qualify as a theft. Probably from the Danish "skæv" or the Dutch "scheef", both of which are pronounced similarly, meaning "askew, or not quite right'. To change an item's ownership without permission, but only something small and of little worth.
"I skeefed an apple off the neighbor's tree." "I skeefed some chips outta your bag when you looked away." "Don't skeef my chair when I go to the bathroom."