sink·hole 
/ˈsɪŋkˌhoʊl/ noun
plural sink·holes /ˈsɪŋkˌhoʊl/ noun [count] : a low area or hole in the ground that is formed especially when soil and rocks are removed by flowing water — sometimes used figuratively ▪ The new highway is a financial sinkhole. [=something that constantly uses up money, resources, etc.]
