bakku-shan (Japanese) – a girl who appears pretty from behind but not from the front
Kummerspeck (German): grief bacon- it is the word that describes the excess weight gained from emotion-related overeating.
Drachenfutter (German): Literally translated as dragon fodder – are the peace offerings made by guilty husbands to their wives.
Aviador – (Spanish speakers in central America) : a government employee who only shows up on payday.
Tingo – (Pascuense language of Easter Island): To borrow objects from a friend’s house, one by one, until there’s nothing left.
All from this BBC article
The article is based on The Meaning of Tingo: And Other Extraordinary Words from Around the World by Jacot De Boinod.
They Have a Word for It : A Lighthearted Lexicon of Untranslatable Words and Phrases by Howard Rhiengold.