Used as a verb, to calque means to borrow a word or phrase from another language while translating its components so as to create a new lexeme in the target language.
Calque is a loanword from a French noun, and derives from the verb calquer (to trace, to copy). The word “Loanword” is a calque of the German word Lehnwort, just as “loan translation” is a calque of Lehnübersetzung.
Proving that a word is a calque sometimes requires more documentation than does an untranslated loanword because, in some cases, a similar phrase might have arisen in both languages independently. This is less likely to be the case when the grammar of the proposed calque is quite different from that of the borrowing language or when the calque contains less obvious imagery.
Calquing is distinct from phono-semantic matching. While calquing includes semantic translation, it does not consist of phonetic matching (i.e. retaining the approximate sound of the borrowed word through matching it with a similar-sounding pre-existing word or morpheme in the target language).