The phrase "a decisive weapon" is correct and usable in written English.
It can be used to describe a tool or method that has a significant impact on achieving a particular outcome, often in a competitive or conflict context.
Example: "In the battle for market dominance, innovative technology became a decisive weapon for the company."
Alternatives: "a game-changing tool" or "a critical asset".
Although not a decisive weapon, the 47-foot-long V-2 (the designation stands for Vergeltungswaffe 2, or Vengeance Weapon 2) with its one-ton warhead, was one to inspire dread among Allied civilians and soldiers alike.
Under this circumstance, effective environmental taxation will be a decisive weapon to meet both global and local demands of environmental conservation.
Despite having long since ceased to be a decisive weapon of warfare, when ordered the Australians had unhesitatingly charged towards the Viet Cong machine-guns in the certainty of suffering casualties.
Buy from Amazon.comPROPAGANDA is an essential, sometimes decisive, weapon in war, and not just in modern times.
We now know that the M40 was a decisive ground weapon in the siege.
Because a decisive Confederate weapon was negated, some have concluded that the Union could claim a strategic victory.
For half a century, big missile submarines, known as boomers, have been arguably the most decisive weapon systems in modern warfare – the queen on the strategic chessboard – because of their capacity to remain unseen until the critical moment, unleashing enormous destructive force without warning.
The bayonet, which was relied on by the prewar French Army as the decisive weapon, actually produced few casualties.
By the middle of the 17th century guns arrayed along the sides of fighting ships were the decisive weapon.
By 1560 these guns were used in large battles & in the 1575 Battle of Nagashino they were the decisive weapon.
In Benghazi, air power has proved the decisive weapon in the government arsenal, wearing down Islamist brigades including Ansar al-Sharia, which was blacklisted as a terrorist organisation by the UN last week.
