I use the title guardedly, as these words featured and illustrated by Ella Frances Sanders at Maptia are all perfectly translatable, but as phrases rather than as neat single words. There’s probably a neat word in a language somewhere that we could use to describe concepts-as-single-words that can’t be translated into single words in other languages. We could of course make one up, say, we could call them uniglottal, i.e. existing as a word in only one language. Words like this get borrowed pretty quickly if they’re useful enough, for example, Schadenfreude — and while words get borrowed all the time, here they’re a special kind of loan word, describing an idea rather than a thing.
One of the words in the list, the lovely Japanese word komorebi reminded me of a word that’s been sufficiently borrowed long enough not to be included in lists like this anymore: bokeh, which is well-known in photography, and like a lot of loan words doesn’t venture much outside a particular profession or technical niche. Then you get to thinking of it and notice more and more, and it reminds me of a French colleague half-jokingly saying, “You can tell if an English word is one of the ones we brought over*: it has more than one syllable”. Controversial.
If you’re interested in the idea of words like this, Better Than English posts a new one fairly frequently.