Usually they're used when riding a horse. "Giddy up" (gee up) means to start, and "whoa" means to stop. Of course, you'll be digging your heels into the horse's sides, or pulling on the reins when you do this. :)

well giddy up means lets go or get up.you can use the words "whoa" when you are passing in extreme things like jumping in high river,driving so fast you can scream it when ever things that your doing that you think was great. cowboy...