Sui generis
Sui generis (; ) is a Latin phrase that means "of its (his, her, their) own kind; in a class by itself; unique."
South African family law
An engagement, which is an agreement "sui generis", is generally defined in the common law as "a legal agreement between a man and a woman to marry each other on a specific or determinable date." Despite the constitutional developments discussed previously, this definition remains in place today.Consensus is prevented, "inter alia", by mistake, misrepresentation, "metus" and undue influence.