nutcase

He called his neighbor a nutcase after she shouted at the mailman every morning.

他每天早上对邮递员大喊大叫，他说邻居是个疯子。

The movie's villain is a complete nutcase who laughs while destroying the city.

电影里的反派是个十足的疯子，一边毁掉城市一边大笑。

Don't listen to his plan; he's a nutcase who thinks aliens live in his basement.

别听他的计划，他是个疯子，觉得外星人住在地下室。