I have some additions to this list of words in other languages that don’t have English equivalents.
Saudade (Portuguese) – Missing something or someone that may not even exist.
Other favorites not on this page:
Schadenfreude (German): Taking delight in the misfortune of another.
And Oofda (Norwegian): Indicates sensory overload. An expression of surprise, astonishment, exhaustion, relief and sometimes dismay. The term has been heard among men when a particularly attractive woman enters a room, or depending on the tone of voice, when a particularly unattractive woman enters the room. [ Also, something one might say when stepping in cold cat barf upon getting out of bed. ~XineAnn ]
Gemutlichkeit (German): cozy content time with people you care about.
Tartle – Scottish: to hesitate when you are introducing someone whose name you can’t quite remember.
Some words I liked here:
Waldeinsamkeit (German): The feeling of being alone in the woods.
Esprit de l’escalier (French): A witty remark that occurs to you too late, literally on the way down the stairs.
Meraki (Greek): This is a word that modern Greeks often use to describe doing something with soul, creativity, or love — when you put “something of yourself” into what you’re doing, whatever it may be. Meraki is often used to describe cooking or preparing a meal, but it can also mean arranging a room, choosing decorations, or setting an elegant table.
The rest of the list:
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
Taarradhin (Arabic): a way of resolving a problem without anyone losing face (not the same as our concept of a compromise – everyone wins)
Litost (Czech): a state of torment created by the sudden sight of one’s own misery
Yoko meshi (Japanese): literally “a meal eaten sideways”, referring to the peculiar stress induced by speaking a foreign language:
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.
Guanxi (Mandarin): in traditional Chinese society, you would build up good guanxi by giving gifts to people, taking them to dinner, or doing them a favour, but you can also use up your gianxi by asking for a favour to be repaid.
Pochemuchka (Russian): a person who asks a lot of questions
Tingo (Pascuense language of Easter Island): to borrow objects one by one from a neighbour’s house until there is nothing left
Radioukacz (Polish): a person who worked as a telegraphist for the resistance movements on the Soviet side of the Iron Curtain
Selathirupavar (Tamil): a word used to define a certain type of absence without official leave in face of duty
Also, suggested by Seb: Pakikisama (Tagalog): Valuing friendships in a group over individual momentary interests.
From DayWhite: Sabsung (Thai) , the literal definition being, “to slake an emotional or spiritual thirst; to be revitalized.” When life becomes a desert, sabsung is what you, personally, need to come back to life; it’s your ladle of water, your quiet time, a beer and the game, a bubble bath, whatever it takes for you to keep going after a hard day. It’s like the effect some people can have on you. They make you happy to be alive, reawaken you to the fact that you are actually alive. That’s sabsung.
From Inga: ilunga – Tshiluba (Southwest Congo) – A word famous for its untranslatability, most professional translators pinpoint it as the stature of a person who is ready to forgive and forget any first abuse, tolerate it the second time, but never forgive nor tolerate on the third offence.