(adjective) word Cool, highly impressive, intricate, unusual or (for a person) someone savvy & canny.
Outdated slang (by the 1990s) for a person or gadget. "Whiz" as abbreviation for "wizard", i.e. indicating the Wizard of Oz with his lightshows and gadgets.
He's the whiz kid! (the wonder kid)
That new multi-function toy is really whiz!