Here are top 5 words not found in English. Some of them would definitely be useful for English-speakers, what do you think?
1. Waldeinsamkeit (German): the feeling of being alone in the woods
2. Ilunga (Tshiluba, Congo): a person who is ready to forgive any abuse for the first time, to tolerate it a second time, but never a third time.
3. Litost (Czech): a state of torment created by the sudden sight of one’s own misery
4. Duende (Spanish): a climactic show of spirit in a performance or work of art, which might be fulfilled in flamenco dancing, or bull-fighting, etc.
5. Selathirupavar (Tamil): a word used to define a certain type of absence without official leave in face of duty