The joint
Freud’s essay is not only about a mood. It is about a word whose positive form already contradicts itself. Heimlich is what belongs to the house, and it is what is hidden. Unheimlich is the negation of the cozy sense, and it coincides with the secret sense. Take the stem away and the essay’s first move, the dictionary move, has nothing to grip.
“The uncanny” is nevertheless the right English title, because English already had a word for the feeling. The cost is structural. A reader can follow the argument about the return of the repressed. They cannot watch it happen inside the title, unless the translator keeps pausing to say un-homely. “Unhomely” is sometimes used for that reason. It is ugly, and it is the mechanism.
French inquiétante étrangeté is an open paraphrase: strangeness that makes you uneasy. Japanese 不気味なもの is the eerie thing. Both carry the shudder. Both leave the house outside the word. That is a connotation break in the strict sense: the neighboring senses that make the German word an argument are not neighbors of the translated word.
Why this break matters to a reader
A reader of “the uncanny” learns a concept Freud is defining. A reader of das Unheimliche watches the definition fall out of a word they already use. The essay’s uncanniness is partly that ordinary German turns over in the hand and shows a secret side. In translation, that turn has to be told. Telling is not a failure. It is a different crate, and the crate was the trick.