Wiktionary
n. (context legal US English) violation of an imaginary or trivial law
Wikipedia
Mopery is a vague, informal name for minor offenses. The word is based on the verb to mope, which originally meant “to wander aimlessly”; it only later acquired the sense "to be bored and depressed". The word mope appears to have first been used in the 16th century, and appears in Shakespeare's works. It has occasionally been put into use by police as a charge to bring when no other legitimate charge seems appropriate. It has also been used for satiric and/or comedic effect in books and films.
Usage examples of "mopery".
This was Captain Cozenage, whose record while in charge of the Homicide Squad was without parallel in the annals of crime: as a result of which he had been, in rapid succession, switched to the Loft Robberies, Pigeon Drop, Unlicensed Phrenologists, and Mopery Squads: and was now entrusted with a letter-of-marque to suppress steamboat gamblers on the East River.
Losian of every crime from barratry to mopery and dopery in the spaceways.
But Captain Krausa listened quietly, then answered with real poetryhe accused the Losian of every crime from barratry to mopery and dopery in the spaceways.
A little trouble next morning- Seems that one Simon Legree, licensed dealer in slaves, had sworn a complaint against me alleging bodily harm, mental duress, and assorted mopery and dopery.