Were, from the prefix form, "were-" - which, in turn, is generalised from "werewolf", "werebear", etc - indicates a class of creature that can shape-shift.

The shifting may or may not be at the creature's volition. In the case of many lycanthropes, the transformation from human to wolf form is controlled by the phase of moon. Generally, one of the two forms is human and the other some animal.