prescriptivism Definition

1. grammar.
An authoritarian approach to language which advocates the strict application of certain rules governing how it should and should not be used, eg the avoidance of split infinitives or the use of ‘I shall' rather than ‘I will' to express future time. It is now generally frowned upon by linguists, teachers, etc because it fails to take into account how language is used and its potential for creativity.
2. philos.
The theory that moral judgements prescribe some course of action. Compare descriptivism.