Any time somebody brings up the claim that the German language has words for everything, somebody will inevitably point that that’s just how German works: you can glue nouns together to create a single word where English would use a phrase, so German having lots of words with very specific meanings is no more remarkable than English having lots of phrases with very specific meanings.
That’s true as far as it goes, but I think it’s overlooking the really fun part.
A lot of those glued-together words have meanings that aren’t simply the sum of the meanings of the words that comprise them. Again, this is not remarkable; English has phrases whose meanings aren’t obviously derived from the words they contain, too - they’re called idioms. In English, idioms are phrases by definition, but since German can produce single words that play the role that phrases do in English, German can have single-word idioms. Straightforward.
Now here’s the fun part: this being the case, it’s technically correct to say that the German language has words whose meaning cannot be derived from their meaning.