noun
Used in computing contexts to indicate that a value, parameter, or behavior has not been explicitly defined or set.
この変数は未規定のままでは使えません。
This variable cannot be used while it remains unspecified.
未規定の動作に依存したコードは避けるべきだ。
You should avoid code that relies on unspecified behavior.
Compound of 未 (mi, 'not yet') and 規定 (kitei, 'regulation, specification'). The term is used primarily in technical and computing contexts.