grandfather clause: Meaning and Definition of

grand'father clause"

1. a clause in the constitutions of some Southern states after 1890 intended to permit whites to vote while disfranchising blacks: it exempted from new literacy and property qualifications for voting those men entitled to vote before 1867 and their lineal descendants.
2. any legal provision that exempts a business, class of persons, etc., from a new government regulation that would affect prior rights and privileges.