But in English, as the territory was part of Prussia and Poland's claims recognised by no-one - you simply cannot use the term "occupation".
If there was at least one country that didn't recognize the partitions of Poland and protested against them, would it mean that Poland indeed was under occupation?
Why? It wasn't occupied.
It might not be what Poles want to hear, but facts are facts.
What I meant was the use of the term "Polish occupation" in the following cases: "Polish occupation of", "lands under Polish occupation".
I don't call a vast amount of collaboration with them "defiant".
What is collaboration in such circumstances? Working in Prussian bakery to feed one's family?
Certainly, they rejected the annexation and considered it occupied - but that was in their mind, not in the world's mind.
For the record, the terms: "Prussian Poland", "Austrian Poland", "Russian Poland" were in use when Poland wasn't formally on the map of Europe, e.g. "Higher education in Russian, Austrian, and Prussian Poland (1896)", published by U.S. Government Printing Office; The encyclopædia of geography
(1837) See more here