Mamihlapinatapei (Yagan): The wordless yet meaningful look shared by two people who desire to initiate something, but are both reluctant to start.
Yuanfen (Chinese): A relationship by fate — but “fate” isn’t the same thing as “destiny.” Even if lovers are fated to find each other they may not end up together.
Cafuné (Brazilian Portuguese): The act of tenderly running your fingers through someone’s hair.
Retrouvailles (French): The happiness of meeting again after a long time.
Ilunga (Bantu): A person who is willing to forgive abuse the first time; tolerate it the second time, but never a third time.
La Douleur Exquise (French): The heart-wrenching pain of wanting someone you can’t have.
Koi No Yokan (Japanese): The sense upon first meeting a person that the two of you are going to fall into love one day.
Forelsket: (Norwegian): The euphoria you experience when you’re first falling in love.
Saudade (Portuguese): The feeling of longing for someone that you love and lost. A vague and constant desire for something that does not and probably cannot exist.
— from The Top 10 Relationship Words That Aren’t Translatable Into English by Pamela Haag