General opposites:
* Foolish: This is a straightforward, common opposite. It suggests lacking good judgment and common sense.
* Unwise: This is a direct antonym, but less strong than "foolish."
* Stupid: This is a more harsh term, suggesting a lack of intelligence.
More specific opposites:
* Ignorant: This emphasizes a lack of knowledge or understanding.
* Naive: This suggests a lack of experience and worldliness.
* Imprudent: This focuses on poor judgment and recklessness.
* Rash: This implies acting without thinking, impulsively.
* Unthinking: This emphasizes a lack of careful consideration.
The best word to use will depend on the specific context and the nuance you want to convey.