I'm afraid you are mistaken, Octavius. Polly is not of German descent and does not mean smart in German. Here is a copy of one of the many explanations of the Name:
The girl's name Polly \p(ol)-ly\ is pronounced PAH-lee. It is of English and Irish origin. Variant of Molly; nickname of Mary (Latin) "star of the sea". Actress Polly Bergen.
Polly has 6 variant forms: Poll, Pollee, Polley, Polli, Pollie and Pollyanna.
Various sites give different meaning of the name from "beloved" to "sorrow" and the like.