A stratagem is a scheme or a clever plot. You can have a stratagem for winning a chess game, getting the girl (or boy), and avoiding a punishment. However, your opponents, crushes, and parents may have a trick or two of their own.
Sometimes a stratagem is a gem of an idea, really clever and worth trying. Great generals start a battle plan with a stratagem, and businesses might have a stratagem for making more money. A stratagem is often a trick or a way to deceive an enemy or get something through a plot or ploy, but it can also mean just a great idea that outwits someone. Your teacher probably has a stratagem for helping you remember and spell words.
n an elaborate or deceitful scheme contrived to deceive or evade
something planted secretly for discovery by another
an illegal scheme for making money by manipulating stock prices; the schemer persuades other people to buy the stock and then sells it himself as soon as the price of the stock rises
an instance of accomplishing something by scheming or trickery