much/still less idiom formal
更不用说，更别提
used to make a negative statement stronger
At the age of 14 I had never even been on a train, much less an aircraft. 我14岁时还从未坐过火车，更不用说飞机了。
英汉双解词典收录81607条英汉双解翻译词条，基本涵盖了全部常用单词的读音、翻译及用法，是英语学习的有利工具。