non-prescriptive

adjective

1. that prescribes; giving directions or injunctions: a prescriptive letter from an anxious father.
2. depending on or arising from effective legal prescription, as a right or title established by a long unchallenged tenure.

adjective

1. making or giving directions, rules, or injunctions
2. sanctioned by long-standing usage or custom
3. derived from or based upon legal prescriptiona prescriptive title

adj.1748, from Late Latin praescriptivus, from praescript-, past participle stem of praescribere (see prescription). Or formed in English from archaic prescript “a direction” (1530s), from Latin praescriptum.