mamihlapinatapai

From a Yámana word mamihlapinatapai, which The Guinness Book of Records listed as the "most succinct word," defining it as "looking at each other hoping that either will offer to do something which both parties desire but are unwilling to do." The word is a regularly-derived form of the verb ihlvpi /iɬəpi/, meaning "to feel awkward" or "to be at a loss for what to do": ma[m]- refl/recp + ihlvpi + :n[a]- stative + -at[a]- caus + -a:pai du. Its literal meaning is therefore roughly "to make each other both feel awkward".

来源：wiktionary