Perhaps you should try some spelling variations:
passiver » passive, passiven, passively
massiv » massive
passiveeren » passieren, passiverer, passivierende
massigeren » massiger, massigen, massivere
passivieren » passivierende, passivierung, passieren

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((passiver OR massiv) OR (passiveeren OR (massigeren OR passivieren)))*.