blue law

noun2

1. •
   (US, Canada) Any puritanical or restrictive law, especially one that prohibits or restricts commercial activity on a Sunday.
2. •
   (US, Canada) A restrictive religious-based law in colonial New England, especially preventing leisure activities on a Sunday.

   • Years ago, because of the Blue Laws, we couldn't serve drinks on Sunday over the bar, so we set up tables in the aisles. And we'd have different acts on a stage up front. — 1976