What is "passive data structure" in Android/Java?

I think the idea is that the Intent doesn't know how to do the activity, it only contains the info to describe what needs to be done. it's up to the receiver to actually enact the action using the Intent's information. hence, the Intent is "passive" in regards to the resulting action.

A passive data structure (opposite of active data structure, or functional data structure) is one that is managed exclusively by external threads. That is to say, it does not have some associated thread which performs operations on it.

Basically, it's like a container of information; you create it, set all its information, and it just exists to be accessed by other processes (in Android, Activity objects, usually). Hence, it is not actively being access (so it's not "active"), and it is not being operated on (not "functional"), so it should be considered passive.