Green’s Dictionary of Slang

knobstick n.

also nobstick
[SE knobstick, a club with a rounded head, used by strike-breakers as a weapon]

[mid-19C–1920s] a strike-breaker.

In compounds

knobstick wedding (n.)

[mid-19C+] a wedding forced on a couple when the woman has become pregnant out of wedlock [in an act of George II, any woman not married but already pregnant could be arrested and compelled to name the father. The same act empowered the parish officers to arrest the father and imprison him unless he married the mother or gave bail to appear when the child was born].