Is a weasel a prey or a predator?

Answer 1

both, they hunt other small mammels and things and are hunted by larger mammels.

Addition:

Weasels feed on small mammals, and have from time to time been considered vermin since some species took poultry from farms, or rabbits from commercial warrens. Certain species of weasel and ferrets have been reported to perform the mesmerizing weasel war dance, after fighting other creatures, or acquiring food from competing creatures. So in this case they are predators.
The weasel does not have many friends. Animals much bigger than it do not dare come near. Some say the weasel will kill without reason even though it is not hungry. It is not afraid to fight a bear or a porcupine.

Weasels are as curious as racccons. They look under every bush and sneak into holes.