The story
Mamihlapinatapai comes from Yaghan, the language of the Yaghan people of Tierra del Fuego, at the southern tip of South America. It reached the rest of the world through The Guinness Book of Records, which listed it as the 'most succinct word' and defined it as two people looking at each other, each hoping the other will offer to do something both want but neither is willing to do.
The word is less exotic than its length suggests. It is a regular verb form built from parts: ma(m)-, which makes the action mutual, the root ihlapi, 'to be at a loss what to do next', and suffixes for a state, an outcome and two people. A rough literal reading is 'to make each other feel awkward'. Most of what is known about older Yaghan comes from the dictionary compiled by the missionary Thomas Bridges in the nineteenth century.
English has a word for the situation, standoff, but none for the look. Writers on game theory borrow mamihlapinatapai for the volunteer's dilemma, where everyone waits for someone else to act.
A scene: two people reach a narrow doorway at the same moment. Each gestures 'after you', neither moves, and for a second they simply look at each other. The writer Mark Forsyth used that very picture to explain the word.
Yaghan has no native speakers left. Cristina Calderón, the last, died in 2022.