Perhaps you should try some spelling variations:
passiven » passive, passion
passiveren » passivieren, passiver, passageren
massigeren » massigen, massivere, massierer, massingeren, massiveen, massieen
massiger » massinger, massive, massie
passiveeren » passivieren, passivierende, passivierung
passieren » passiert
passiverer » passiverwerb, passivieren, passiver

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: (passiven OR (passiveren OR ((massigeren OR massiger) OR ((passiveeren OR passieren) OR passiverer)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(passiven or (passiveren or ((massigeren OR massiger) or ((passiveeren or passieren) or passiverer))))".
• Adding a wildcard symbol may retrieve word variants: (passiven or (passiveren or ((massigeren OR massiger) or ((passiveeren or passieren) or passiverer))))*.