In law, it means person filed or intermediary, who would fulfill the function of acting in appearance of any type of legal business will, but actually acting under the mandate and for the benefit of a third party, who does not want to or must not appear formally in the same. They are business-anomalous there is simulation.
A person, appearing in a legal act, without real interest, as part to favour the interest of another person who, for reasons not generally lawful at all, you want to hide his involvement in the business.