The word "nutjob" is informal and derogatory, typically used to describe someone who behaves in a strange, crazy, or irrational manner. Full definition
If he does get the nomination, it will be because there is a disturbingly high number of religious nutjobs like you out there who are voting for him. (religion.blogs.cnn.com)
there are a lot of nutjobs out there who believe some of the craziest nonsense. (religion.blogs.cnn.com)
As much as I disagree with Romney's religion as a whole, Romney isn't a religious nutjob like Santorum. (religion.blogs.cnn.com)