I would say schadenfreude, angst, cri de coeur, paparazzi, proviso, and auteur are useful loanwords that have no simple or direct equivalent in English (btw my spellchecker demands a German capital for schadenfreude as with realtor). There must be others.
Grey areas would be zeitgeist (spirit of the age works just as well? (and the spellchecker lets that through!)); et al (and others); sui generis (unique); &c.
Some have specific applications such as legal pro bono, philosophical a priori, a posteriori, and these have stuck after prolonged usage.
Cul de sac (dead end) and entre nous (between you and me) are unnecessary and pretentious I would say and there must be many more of these. Part of it must be that writers (or speakers) feel they are erudite and eloquent if they go for the foreign over the homegrown.
Finally, are there any English loanwords in other languages that have no equivalent as in my first para? ‘Le dirty weekend’ in French is the only, er, conceptual one I can think of.
Hope this hasn’t been covered before, possibly by me - I found it in my old notes after being reminded by the slip in in last post
