Wiktionary
four l
alt. A law student in his or her fourth year of law school; generally an unusual situation occurring where a student has either taken an extended part-time curriculum, or has failed a class needed for graduation and must stay on for an extra semester after the three L year. n. A law student in his or her fourth year of law school; generally an unusual situation occurring where a student has either taken an extended part-time curriculum, or has failed a class needed for graduation and must stay on for an extra semester after the three L year.
Wikipedia
Four L