WordNet sense 1 (youngest son of Henry II; King of England from 1199 to 1216; succeeded to the throne on the death of his brother Richard I; lost his French possessions; in 1215 John was compelled by the barons to sign the Magna Carta (1167-1216)):

John Lackland, King John

WordNet sense 2 ((New Testament) disciple of Jesus; traditionally said to be the author of the 4th Gospel and three epistles and the book of Revelation):

Saint John, St. John, John the Divine, John the Evangelist, Saint John the Apostle, St. John the Apostle

WordNet sense 3 (a prostitute's customer):

trick, whoremaster, whoremonger

WordNet sense 4 (the last of the four Gospels in the New Testament):

Gospel According to John

WordNet sense 5 (a room or building equipped with one or more toilets):

bathroom, can, lavatory, privy, toilet, lav