CV axle

You will die in a horrible flaming car crash!

Well, okay, it is not quite that bad, but what are you trying to solve? I had to guess you are referring to a front half shaft. The outer CV joint is what clamps the wheel bearing together, and the tightness of that axle nut is very high and critical. If you are lucky, driving the vehicle without that joint in place will only instantly cause the bearing to become noisy and make a buzzing noise, like an airplane engine. More likely the bearing will come apart and let the bottom of the wheel squirt out. That can damage the brake caliper's mount, and the twisting caliper will push its piston in to the retracted position. When you apply the brakes, the pedal will go to the floor as the fluid tries to run the piston back out. You may be found in the next county with the brake pedal still pushed to the floor. That alone can damage the master cylinder.

Here's a picture of the half shaft. The red bracket shows the outer CV joint. That part has to be in the wheel bearing to hold it together. If you don't want to destroy the original shaft, or don't know how to remove the joint from the shaft, you may be able to find a used joint at a salvage yard. They sell used shafts to the rebuilders, but the joints get replaced anyway, so they shouldn't care if an old one is missing. Be aware though, the guys who do the dismantling have to work real fast, and they will likely use a torch to cut the shaft off. That would leave you with part of the shaft that could cause an out-of-balance condition. It is very unlikely that would be bad enough to feel. You don't need the rubber boot or the band clamp.

You also have to look at how the inner CV joint, (my nifty blue arrow), is held in. On most vehicles the spring pressure in the inner CV joint pushes the mating shaft into the differential housing and holds it there. Some of those mating shafts are held in with circlips, which are wire rings on the end of the shaft. If you've also removed the front drive shaft between the transfer case and front axle, I would just tie a piece of wire to that stub shaft to insure it doesn't fall out. If it feels real tight when you tug on it, you likely don't even have to worry about it falling off.