descriptivismnoun [ U ]
/dɪˈskrɪp.tɪ.vɪ.zəm/specialized language the belief that books about language should describe how language is really used, rather than giving rules to follow saying what is correct and not correct:
There has been a blurring of the sharp distinction between descriptivism and prescriptivism in the writings of grammarians and lexicographers.
Compare
prescriptivism