A meat tenderizer is a device used to soften meat by breaking down its fibers. The tenderizer is a hand-powered tool similar to a mallet, with small pyramid-shaped metallic fragments attached to the head of the device. In order to soften the meat you hit it with this device.
Tenderizing a piece of meat makes it easier to chew, and easier for your stomach to digest. Meat tenderizing should occur either during or before preparation. Marinades flavor meat, but are ineffective when it comes to tenderization. Acidic marinades tend to toughen the meat rather than tenderize it, and enzymatic marinades cause the meat to become mushy.