New American Oxford Dictionary
plughole
plug |hole |ˈplʌghəʊl | ▶noun Brit. a hole at the lowest point of a bath, basin, or sink, down which waste water drains away and which can be stopped with a plug. PHRASES go down the plughole informal be unsuccessful, lost, or wasted: the company went down the plughole.
Oxford Dictionary
plughole
plug |hole |ˈplʌghəʊl | ▶noun Brit. a hole at the lowest point of a bath, basin, or sink, down which waste water drains away and which can be stopped with a plug. PHRASES go down the plughole informal be unsuccessful, lost, or wasted: the company went down the plughole.
Sanseido Wisdom Dictionary
plughole
pl ú g h ò le 名詞 C ⦅英 ⦆排水口 〘栓でふさぐもの 〙 (⦅米 ⦆drain ).g ò down the pl ú ghole むだに費やされる ; 失敗する .