How do English-speaking people more commonly refer to what is called "Der Sitzkrieg" in German?
"Sitzkrieg" - meaning, literally "sitting war" in German is an alternative name for the first eight months of the Second World War when there was relatively little action.
Neville Chamberlain, the then British Prime Minister, declared war on Germany on the 3rd of September, 1939, following Hitler's invasion of Poland. At this point in the war, the USSR was still an ally of Nazi Germany, and their troops also participated in the invasion. The waters were further muddied by the USSR invading Finland in November of that year.
The truth was, that although the leaders of the Western Allies thought they had little choice but to declare war, there was little appetite for it in some quarters and the Frenchman Marcel Deat even launched the provocative slogan "Why die for Danzig?" (present-day Gdansk). As he later collaborated with the Nazis, it is unlikely that pacifism was his motive! The phrase, incidentally, passed into the Polish language with the symbolic meaning of "an argument nobody should agree with".
There was so little apparent action that some British children who had been evacuated as a safety precaution were recalled home.
Eventually, though, this limbo situation came to an end, with the Nazi invasion of the Low Countries in May 1940, leading not long after to the Invasion of France, the evacuation of Dunkirk, and conflict affecting people the world over and leading to millions of deaths, and lasting for five long years.