grandfather clause

/ˌgræn(d)fɑðər ˌˈklɔz/

Other forms: grandfather clauses

A grandfather clause is a provision in a legal document that allows an old rule to apply to some people while a new rule is enacted for most people.

The language in a law sometimes includes a grandfather clause that makes an exception for an existing situation. For example, people who have rented out rooms in their houses for years may not be affected by a law banning the practice going forward — thanks to a grandfather clause. The original 1899 grandfather clause allowed men whose grandfathers had the right to vote to be exempted from a new rule requiring voters to own property and to be able to read.

Definitions of grandfather clause

1. noun

   an exemption based on circumstances existing prior to the adoption of some policy; used to enfranchise illiterate whites in south after the American Civil War
   type of:

   exemption, freedom

   immunity from an obligation or duty