not law.A judicial decision regarded as wrong by the legal profession.

“Even when it is not possible to point out any decision that affects the point in question in any one of the ways enumerated, it sometimes happens that the profession has grown to ignore the old decision as wrong or obsolete; and though this does not happen often, when it does happen, the old decision is very likely not to be followed in case the point is squarely raised again. This is one of the instances in which lawyers rather mystically, though soundly, say that a decision is ‘not law.’ ” William M. Lile et al., Brief Making and the Use of Law Books 329 (3d ed. 1914).

[Blacks Law 8th]