The term THEY'RE NOT RETURNED can be broken down into two crossword solutions: ACES (4 letters) and TENNISACES (10 letters). ACES is a term used to describe a hand of cards in which all four cards are of the same rank. In card games, this is the highest ranking hand and is unbeatable. TENNISACES is a term used to describe a situation in tennis where a player has won all four points in a game. This is also known as a 'clean sweep' or a 'perfect game'.