Alia juris

What does Alia juris mean in American Law?

The definition of Alia juris in the law of the United States, as defined by the lexicographer Arthur Leff in his legal dictionary is:

Under the authority of someone else (e.g., parent or guardian) for legal purposes. The term is not quite the opposite of “sui juris,” for one can be “not sui juris,” e.g., insane, and still not be “alia juris,” because no guardian or other legal representative has been appointed.