What is the verb form of stupidity?

There isn't a direct verb form of "stupidity." The concept of "stupidity" is a noun, describing a lack of intelligence or a foolish act.

Here are some verbs that relate to the concept of stupidity:

* Be stupid: This is the most direct way to express the concept as a verb. For example, "He was being stupid by driving too fast."

* Act stupidly: This emphasizes the act of doing something foolish. For example, "She acted stupidly by trusting him with her money."

* Do something stupid: This focuses on the specific action. For example, "They did something stupid by not wearing seatbelts."

* Make a stupid mistake: This emphasizes the error in judgment. For example, "I made a stupid mistake by forgetting to lock the door."

You can also use adjectives like "stupid" or "foolish" to describe actions or people.

Remember that using these verbs can be subjective and potentially insulting, so it's important to be mindful of the context and your audience.