The crossword solution for the term 'SECRET ___' is 'SPY', which is a five-letter word. A SPY is an individual who is employed by a government or other organization to secretly collect information or intelligence about another country or group. Spies often use disguises, false identities, and other methods of deception to carry out their mission. They may also be involved in sabotage, espionage, and other activities that are considered illegal in some countries. Spies have been used throughout history to gain an advantage in warfare and politics.