The phrase "this ploy" is grammatically correct and can be used in written English.
Example: This ploy of pretending to agree with her just to avoid an argument was getting exhausting.
This ploy has been only partly successful.
This ploy is already fully transparent.
This ploy permitted comparison between species in which weights have different meanings.
This ploy gives Goode a yard of space to ghost through and break the line.
This ploy works: female tennis players are some of the highest-earning athletes around.
This ploy came to mind last Thursday evening, when the smell of maple syrup unaccountably permeated the entire metropolitan area.
This ploy came to mind last Thursday evening, when the smell of maple syrup unaccountably permeated the entire metropolitan area….. Recently, the market has cooled off.
"This ploy will not work," he said in a speech at a conference held Friday by the Foundation for the Defense of Democracies.
This ploy might work at the state level, but at the federal level even senior Bush people admit it is backfiring.
This ploy can't work forever.
This ploy represents a misuse of the doctrine of "rescue of nationals abroad".
