As a noun, ideal means (1) a conception of something in its absolute perfection, or (2) an honorable or worthy principle or aim. It is not conventionally a variant or synonym of idea, though it is sometimes colloquially used this way.
Example
So, for example, idea should replace ideal in these sentences:
Why defunding NPR is a good ideal [I Conservative]
If you have enough money to hire a private instructor, then I guess it is a great ideal since the instructor’s attention will only be focused on you. [Article City]
These writers use the noun ideal correctly:
However, this ideal isn’t always reached by governments that want their thumbs on the economy and, more particularly, the revenue it represents. [Small Business Trends]
The pluralistic ideal that many communities strive for is an unattainable goal. [New Voices]
We have failed those ideals, utterly and spectacularly, more than a few times in our relatively short history. [Bellingham Herald]
