Moral constructivism or ethical constructivism is a view both in meta-ethics and normative ethics.
Metaethical constructivism holds that correctness of moral judgments, principles and values is determined by being the result of a suitable constructivist procedure. In other words, normative values are not something discovered by the use of theoretical reason, but a construction of human practical reason.
In normative ethics, moral constructivism is the view that principles and values within a given normative domain can be justified based on the very fact that they are the result of a suitable constructivist device or procedure. Or more precise: constructivism is the result of constructivism.