a humble request for help from someone in authority
"The prisoner dropped to his knees and made a desperate plea for mercy before the judge."
(law) a defendant's answer by a factual matter (as distinguished from a demurrer)
"The lawyer moved to file a plea in abatement, arguing that the court lacked jurisdiction over the case."
an answer indicating why a suit should be dismissed
"The defendant's attorney filed a plea arguing that the evidence was obtained illegally and requesting the court to dismiss the suit immediately."
An appeal, petition, urgent prayer or entreaty.
"The prisoner made a desperate plea to his lawyer to find new evidence before the trial began."
In plain English: A plea is an urgent request for help, sympathy, or mercy made by someone who has done something wrong.
"The prisoner made a heartfelt plea for mercy during his sentencing hearing."
Usage: Use "plea" to describe an earnest request made in hopes of gaining sympathy or favor from someone else. It is often paired with the phrase "in a plea for help," but avoid using it as a synonym for a formal legal defense unless specifically referring to a courtroom setting.
To plead; to argue.
"The lawyer made a passionate plea that his client should be granted mercy."
The word "plea" comes from the Medieval Latin placitum, which literally meant "that which is pleasing." It entered English via Old French to refer to a legal decree or lawsuit.