The phrase "a harmful idea" is correct and usable in written English.
It can be used when discussing concepts, beliefs, or suggestions that may have negative consequences or effects.
Example: "The proposal to cut funding for mental health services is a harmful idea that could lead to increased suffering in the community."
Alternatives: "a detrimental notion" or "a damaging concept."
There is a well meaning but naive, and potentially very harmful, idea currently doing the rounds in youth justice circles.
Society must be protected from the "harmful idea" that "what essentially makes a marriage is romantic-emotional union".
The social meaning may finally liberate us from the simplistic and harmful idea, false for many other reasons as well, that each aspect of our being, either physical or behavioral, may be ascribed to the action of a particular gene "for" the trait in question.
I'm no beauty pageant fan; such events reinforce the harmful idea that women should be valued largely for their appearance, thereby pressuring women to fit into an arbitrary, oftentimes unrealistic standard of beauty.
"It mocks and stigmatizes its victims, tearing down self-respect and perpetuating the harmful idea that our unique physical appearances should be compared to air-brushed notions of 'perfect.' What really matters is our character and humanity.
"It mocks and stigmatizes its victims, tearing down self-respect and perpetuating the harmful idea that our unique physical appearances should be compared to airbrushed notions of 'perfect.' What really matters is our character and humanity.
However, one of the most notable aspects the whole affair has brought up is just how toxic a locker-room culture can be when it is built upon harmful ideas about masculinity and toughness.
But the insidious effects of stigma and harmful ideas about manhood continue.
Animated films powerfully, engagingly and invisibly transmit harmful ideas about gender and gender roles.
