jailhouse lawyer

A non-attorney who dispenses legal advice. Properly speaking, a jailhouse lawyer is a prison inmate who, although not a law school graduate (much less a member of the bar), has the requisite skill to assist other prisoners with such legal matters as preparing and filing appeals, writs, and pardon requests. Much of such knowledge came from personal experience. The phrase also applies to any layman, behind bars or not, who offers legal advice, solicited or not.