a fifth/third wheel idiom US
汽车上挂拖车的轮子;拖车
a wheel on a vehicle to which you attach a trailer, or the trailer itself
冗员，不需要的人；无足轻重的人
someone who is in a situation where they are not needed or are ignored by most people
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。