The term 'Sure Winner' can be represented by two crossword solutions: 'LOCK' (4 letters) and 'Shooin' (6 letters). 'LOCK' is a noun that refers to a device that is used to secure something, such as a door or window. 'Shooin' is an informal term that is used to describe something that is certain to happen or succeed. It is derived from the phrase 'shoe-in, ' which was originally used to describe a horse that was certain to win a race. Together, these two terms represent something that is certain to succeed.