what is the grandfather clause?

Answer 1

depends on where it is used, normally, it means something that doesn't apply to those already who have been doing something, but now it would be illegal.

Say a law is passed that eight year old girls cant get married, until 28 years old. A grand father clause would make those of them between 8 and 28 who were already married, excused from the new law. Ewwweee.