Subreption is a concept in Roman law and, in this tradition, Canon law. In this context, obreption and subreption belong together. The Latin word for subreption is "subreptio", the German is "Erschleichung".
In German philosophy, the concept was used by Christian Wolff (philosopher) and Immanuel Kant to denounce illegitimate claims to empiricity of representations: I can perceive the formation of my will to lift my arm, and I can perceive the lifting of my arm. To say that I know empirically that my will lifted my arm would be a subreption in Wolff's sense.
The Latin phrase for the philosophical concept of subreption is "vitium subreptionis" -vitium: fault, crime, error; subreptionis: creep, stealth, fraud. The German is a literal translation of this Latin phrase: "Fehler der Erschleichung". It can also mean in general a creeping or tacit assumption(s) that is not explicitly given but is hidden either purposefully (as in sophistry) or not (as in a visual illusion).