Perhaps you should try some spelling variations:
passiv » massiv, passiver
passiven » massiven, passiveren, passion
passivener » massivener, passiverener, passioner, passiverer, passiver, passiverwerb
passive » massive, passivere
passioner » passione, passionen, massioner

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: (((passiv OR passiven) OR (passivener OR passioner)) OR passive).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((passiv or passiven) or (passivener OR passioner)) or passive)".
• Adding a wildcard symbol may retrieve word variants: (((passiv or passiven) or (passivener OR passioner)) or passive)*.