subs. (colloquial).An affectedly prim person: male or female. Hence, MISS-NANCYISM = affected nicety; effeminacy.
1883. Philadelphia Times, 2 July. The milksops and MISS-NANCYS among the young men, etc.
1886. Harpers Weekly, 20 March. Ineffable silliness, sneering at the demand for honesty in politics as MISS-NANCYISM.