The term PROPHET SWALLOWED BY A WHALE is a reference to the biblical story of JONAH. JONAH was a prophet who was commanded by God to preach to the people of Nineveh, but instead he tried to flee from God by boarding a ship. During the voyage, a great storm arose and JONAH was thrown overboard, whereupon he was swallowed by a whale. After three days, the whale vomited him out onto dry land, and JONAH eventually fulfilled his mission. The answer to the crossword puzzle is JONAH, which is a five-letter word.