津 is a ford or ferry crossing. In the Analects, Confucius sends his disciple
子路 to ask two farmers the way to the ford, and
陶渊明's 《
桃花源记》 ends
后遂无问津者 'after that, no one asked the way there again'. From 'asking the way' came 'showing interest', used almost only with a negative:
无人问津 'nobody shows any interest'.