prescriptive

[ pri-skrip-tiv ]

/ prɪˈskrɪp tɪv /

that prescribes; giving directions or injunctions: a prescriptive letter from an anxious father.

depending on or arising from effective legal prescription, as a right or title established by a long unchallenged tenure.

Origin of prescriptive

1740–50; prescript + -ive, modeled on descriptive, etc.

pre·scrip·tive·ly, adverb pre·scrip·tive·ness, noun non·pre·scrip·tive, adjective

The fact that some prescriptive rules are valuable does not mean that every grammatical injunction should be obeyed.

Go Ahead, End With a Preposition: Grammar Rules We All Can Live With |Nick Romeo |November 3, 2014 |DAILY BEAST
It was descriptive, prescriptive, and exemplary in its clarity.

Why Is Malaysia Hiding Its Report on MH370? |Clive Irving |April 28, 2014 |DAILY BEAST
Simmons knows she faces an uphill battle—but her goal this time around is to be prescriptive about the problem.

What Makes Mean Girls Tick |Jessica Bennett |August 12, 2011 |DAILY BEAST
In spite of all this, long habit has secured to these pernicious customs a sort of prescriptive right.

Apis Mellifica |C. W. Wolf

The men of the upper classes are not only exempt, but by prescriptive custom they are debarred, from all industrial occupations.

The Theory of the Leisure Class |Thorstein Veblen
The corporation, which was prescriptive, was entitled the mayor, jurats and commonalty of Folkestone.

Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 5 |Various
The most striking instance, however, is the acquisition of prescriptive rights.

The Common Law |Oliver Wendell Holmes, Jr.
The members of the corps had the prescriptive right of choosing the regiment to which they would be attached.

Encyclopaedia Britannica, 11th Edition, Volume 15, Slice 8 |Various

prescriptive

/ (prɪˈskrɪptɪv) /

making or giving directions, rules, or injunctions

sanctioned by long-standing usage or custom

derived from or based upon legal prescription a prescriptive title

prescriptively, adverb prescriptiveness, noun