Demandar
Demandar is a verb used in Spanish and Portuguese with two main senses. Primarily, it means to sue or to bring a legal action against someone in a court. It can also mean to demand or claim something in a formal way, though in everyday Spanish this second sense is more commonly expressed with reclamar or exigir.
In legal contexts, demandar denotes initiating litigation. The person who brings the action is the demandante
Regional usage varies. In Latin America, demandar is widely understood and routinely used in legal discourse
Etymology generally connects demandar to the noun demanda, with roots in Latin through historical legal vocabulary.