Focusing on practicality:
* Realism: This is the most direct opposite of idealism, emphasizing practical concerns and accepting the world as it is, rather than striving for an ideal state.
* Pragmatism: Similar to realism, pragmatism focuses on what works, even if it doesn't align perfectly with ideals.
* Materialism: This emphasizes physical things and sensory experiences over abstract ideas and values.
Focusing on negativity or cynicism:
* Cynicism: This involves a distrust of motives and a belief that people are inherently selfish.
* Pessimism: This focuses on the negative aspects of things and expects the worst.
* Nihilism: This is a belief that life is meaningless and without purpose.
Other options:
* Skepticism: This involves questioning beliefs and refusing to accept things without evidence.
* Fatalism: This is the belief that events are predetermined and unavoidable.
The best antonym for idealism will depend on the specific context in which you are using it.