Virtually every language had a moment like this, when someone (usually some high council on language or a group of influential intellectuals) decided that there are simply too many borrowings from this or that language. But the one that really went through with it is probably Czech. In the 19th century Czech intellectuals in a sense recreated the language and also wanted to rid it of (perceived) Germanisms, so for example they have hudba for "music" and divadlo for "theatre".
And while most languages have similar names for chemical elements (most taken from Greek), like oxygen, hydrogen, nitrogen, etc., Polish has totally different names because of a group of scientists at the turn of 18th century decided that Greek-based names are foreign and Polish people need to have their own brand Polish names. Which for the next 200 years made chemistry lessons more difficult to generations of high school students, as Polish names of elements basically have nothing in common with their symbols.