'Crazy' in the Bible

So David changed his behavior before them and acted like he was crazy in their presence. He scribbled on the doors of the gate, and let his saliva run down his beard.

“Look! You can see the man is crazy,” Achish said to his servants. “Why did you bring him to me?

Do I have such a shortage of crazy people that you brought this one to act crazy around me? Is this one going to come into my house?”