Remembered this thread, while seeing this list on listverse. 10 words you cannot translate into English.
10: Esprit d’Escalier
9: Hygge
8: Kyoikumama
7: Uitwaaien
6: Qualunquismo
5: Bakku-shan
4: Tingo
3: Zalatwic
2: Ilunga
and number one is
1: Biritululo
Biritululo, what a great word. Going to be my new favorite word I think.
The whole list is here, with info on what each word means: 10 Words That Can’t Be Translated To English - Top 10 Lists | Listverse
Note, I didn't copy paste the whole list here, because it also contain a picture to illustrate each word.