Crank
Defined in 2 dictionaries — Black's (1910), Anderson (1889)
Black's Law Dictionary
Henry Campbell Black, M.A. · 1910
A term vulgarly applied to a person of eccontric, ill-regulated, and unpractical menial habits; a person half-crazed; a monomaniac; not necessarily equivalent to "insane person," "lunatic," or any other term descriptive of complete mental derangement, and not carrying any Implication of homicidal mania. Walker v. Tribune Co. (C. Ct) 29 Fed. 827.
A Dictionary of Law
William C. Anderson · 1889
Has no necessary defamatory meaning, any more than to say of one that he is capricious or subject to vagaries or whims. 3 Does not necessarily imply that a man has been guilty of a crime, nor tend to subject him to ridicule or contempt. If the word has such import it should at least be averred and proven.'