Wiktionary
n. (context informal English) A person incarcerated in a prison, jail, etc who has acquired significant knowledge of the justice system and who is able to represent himself in some legal proceedings and to provide legal advice to other prisoners.
Wikipedia
Jailhouse lawyer is a colloquial term in North American English to refer to an inmate in a jail or other prison who, though usually never having practiced law nor having any formal legal training, informally assists other inmates in legal matters relating to their sentence (e.g. appeal of their sentence, pardons, stays of execution, etc.) or to their conditions in prison. Sometimes, he or she also assists other inmates in civil matters of a legal nature.
The term can also refer to a prison inmate who is representing themselves in legal matters relating to their sentence. The important role that jailhouse lawyers play in the criminal justice system has been recognized by the U.S. Supreme Court, which has held that jailhouse lawyers must be permitted to assist illiterate inmates in filing petitions for postconviction relief unless the state provides some reasonable alternative.
Many states in the U.S. have Jailhouse Lawyer Statutes, some of which exempt inmates acting as jailhouse lawyers from the licensing requirements imposed on other attorneys when they are helping indigent inmates with legal matters.
Cases brought by inmates have also called attention to the need for jailhouse lawyers to have access to law libraries.
The Center for Constitutional Rights and National Lawyers Guild wrote The Jailhouse Lawyers Handbook in 2003 for inmates needing rudimentary information on jailhouse lawyering. The Columbia Human Rights Law Review of Columbia Law School publishes A Jailhouse Lawyer's Manual ("the JLM"), intended to help prisoners and jailhouse lawyers appeal their sentence, protest their conditions of imprisonment, etc. The eighth edition was published in 2009. The ninth edition was published in 2011 and is freely downloadable. The tenth edition was published in 2014 and is the most up-to-date version.
Usage examples of "jailhouse lawyer".
He'd always been pretty vain about his looks, had to admit it now with the studio lights gleaming on the strong lineaments of his brow arching in a deprecating sort of way but they'd never brought him anything but trouble and now suddenly here was a place for them, a place for all his anger and strength and talent if you'd call it that and he'd never have made it without the others, the other prisoners when he heard their applause he knew he had something, one buddy in the program in particular kind of a jailhouse lawyer in there for something that would curl your hair tried to help him out on his appeal, told him if you're black in America you're always playing a part, no way around it just got to find the right part to play where you aren't going to take your bows in a cell block and that did it, Oscar?
Something of a jailhouse lawyer in prison, he was preparing his own appeals to seek an early parole.