noun
stratagem
STRAT-uh-jum/ˈstrætədʒəm/
A clever plan for gaining an advantage.
The soldiers use a hollow wooden horse as a stratagem for victory.

Etymology
The Greek word meant an act of a general, particularly a military trick. That connection survives in the modern sense: a clever maneuver intended to outwit an opponent, whether in war or elsewhere.
In context
Back at St. Augustine, Moore attempted a stratagem of subterfuge to make himself master of the fort on December 14th.
More examples
- Her opening offer is a stratagem to learn the seller's lowest price.
- The coach's stratagem draws defenders away from the team's best shooter.
- His elaborate stratagems fail when his opponent refuses to react.
Forms
stratagem · stratagems
strategist noun — Someone who develops plans to achieve goals.