A trap in which a heavy weight falls onto the animal and kills or disables it. These are some of the easiest traps to make for killing small animals, needing no tools for their construction. You simply prop a big weight up with sticks, and place some bait in such a fashion that tacking the bait will topple the weight onto whatever takes it.
A 'deadfall' can also be a tangled mass of fallen branches, trees, and other vegetable matter. Common along smaller watercourses and in deep woods.