characterization of acts done while actor is in state of extreme stress or explosive anger. See also voluntary manslaughter. n. heir Colloquially used to refer to anyone who inherits under a will or otherwise. collateral heir. A descendant through an indirect line, such as the issue of a sibling or cousin. See also issue. heirs and assigns. Archaic. A phrase formerly necessary for the creation of a fee simple. lineal heir. An heir who is above or below the decedent in the direct line of desce...