One word for a harmful idea/plan [closed]

Solution 1:

According to Merriam-Webster, you can use plot:

[ perhaps back-formation from complot ] : a secret plan for accomplishing a usually evil or unlawful end
_{from m-w.com}

Solution 2:

I favor scheme. While it can refer to plans more generally, the connotation is commonly negative. From the Oxford English Dictionary, bold for emphasis:

5 b. Hence, A plan of action devised in order to attain some end; a purpose together with a system of measures contrived for its accomplishment; a project, enterprise. Often with unfavourable notion, a self-seeking or an underhand project, a plot (cf. scheme v., scheming adj.), or a visionary or foolish project. Phrase, to lay a scheme.

And Cambridge Dictionary:

A scheme is also a secret and dishonest plan:

Villains have schemes. Con artists use Ponzi schemes or Pyramid schemes. A "scheme to slander" appears in many search results. Hence:

The whole scheme to slander John was ...

Solution 3:

If the idea is to benefit someone whilst harming someone else, "ploy" could also be used.

From Oxford:

A cunning plan or action designed to turn a situation to one's own advantage.

From M-W:

a tactic intended to embarrass or frustrate an opponent

Solution 4:

Maybe intrigue could work in your context -

Intrigue

: make secret plans to do something illicit or detrimental to someone.

(From Oxford)

Therefore,

The whole intrigue to slander John was... blah, blah...

There is also conspiracy -

Conspiracy

a secret plan by a group to do something unlawful or harmful.