The party against whom recovery is sought in a lawsuit (the same as the respondent in an alternative dispute resolution proceeding).
Merriam-Webster Online Dictionary
defendant (noun)a person required to make answer in a legal action or suit - compare plaintiff
being on the - defensive defending
Defendant (Wikipedia)
In court proceedings, a defendant is a person or object who is the party either accused of committing a crime in criminal prosecution or against whom some type of civil relief is being sought in a civil case.
Terminology varies from one jurisdiction to another. In Scots law, the terms "accused" or "panel" are used instead in criminal proceedings and "defender" in civil proceedings. Another term in use is "respondent".
