Sentence:  Persons whom the Americans since Guiteau's trial have begun to designate as <WSD>‘cranks'</WSD>—that is to say, persons of disordered mind, in whom the itch of notoriety supplies the lack of any higher ambition. 
Meaning of the word marked with <WSD> tags:  A person who is considered strange or odd by others. They may behave in unconventional ways.