does the jimmys vortec have a supercharger? what does the vortec mean?

The Vortec is a series of General Motors engines.
As for a supercharger, I don't know a lot about new model trucks, but I think it comes with a supercharger. I saw some sites with a 2001 GMC Jimmy Supercharger Kit. So....

Vortec implies the design characteristic of the cylinder heads on these engines. The head is designed to produce a kind of a vortex of air and gas entering into the combustion chamber, allowing for better air/fuel mixture, which produces more power, while lowering emissions. The first "vortec" engine was the introduction of the 4.3 in the s-trucks, in 1988. It wasn't really labed vortec until around 1992/1993 when the W engine came out, the CPI engine. Essentially all the 4.3's had a vortec type head.

As well, the 4.3 never came with a s/c even as an option. Look to Powerdyne or www.machperformance.com if you want one.