"ploy against" is a correct and usable phrase in written English.
It is typically used to mean a scheme or strategy devised to gain an advantage over an opponent or rival. For example, "The company used a clever ploy against its competitors to gain an edge in the market."
The Post's View: A peaceful ploy against Venezuela failed.
She added, "It's absolutely shameful to see a professor and teacher pull this kind of ploy against students".
And inside G.M. some executives questioned whether Mr. Ergen's bid was serious or just a negotiating ploy against Mr. Murdoch.
IBM, for example, pays an army of programmers to work on Linux, both for the greater good and as a competitive ploy against Microsoft.
Two months ago, Cragg Hines of The Houston Chronicle wrote that "Gore has repeatedly tried the weekly debate ploy against Bradley, who has refused to take the bait".
One is tempted to wonder, amid lurid cocktails and exhibitionist patrons, if the whole thing might not be Angelenos' revenge ploy against the city that gave them Paris Hilton.
One respondent told researcher: "We bolster our systems to prevent cyber-attacks, yet we find that social engineering ploys against users will sometimes get past these systems.
That afternoon the journalists get wind of a big story: "The Island's most hush-hush establishment, High Haven, base for Britain's cloak-and-dagger ploys against Red China, has been summarily shut down".
GOP presidents Reagan, Bush Sr., and especially George W. Bush in 2004 in his reelection fight with Democratic presidential foe Massachusetts Senator John Kerry, used this ploy masterfully against their Democratic opponents.
That ploy worked well against elusive quarterback Lamar Jackson and Baltimore, but not so well against Hall of Fame-bound Tom Brady and the more bruising New England Patriots offensee.
It could be a with-me-or-against-me ploy.
