A more thorough explanation:

Quaerens (kweer-enz), n. [Law Latin] Hist. One who complains; a plaintiff.

Quaerens is a legal term that refers to a person who brings a complaint or a lawsuit against someone else. In other words, a quaerens is a plaintiff.

Example 1: In a court case, the quaerens is the person who is suing someone else. For instance, if John sues Jane for breach of contract, John is the quaerens.

Example 2: In a criminal case, the quaerens is the victim or the victim's family. For example, if a person is charged with murder, the quaerens would be the family of the victim who is seeking justice for their loved one.

These examples illustrate how a quaerens is someone who initiates legal action against another person. They are the ones who are seeking a resolution to a legal dispute or a crime.