subs. (old).—See quot.
1847. HALLIWELL, A Dictionary of Archaic and Provincial Words, etc., s.v. MUMPSIMUS. An old error in which men obstinately persevere: taken from a tale of an ignorant monk, who in his breviary had always said MUMPSIMUS instead of sumpsimus, and being told of his mistake, said, ‘I will not change my old MUMPSIMUS for your new sumpsimus.’
