语言学家对俚语没有简单明确的定义，但他们一致认为，俚语是一种不断变化的语言现象，存在于世界各地的亚文化中。俚语是一种非正式的词汇(单词、短语和语言用法)，常见于口头交谈，但在正式写作中避免使用。因为俚语并不总是从字面意义上讲得通，所以您需要熟悉每个俚语的意思和用法。英语俚语是日常英语的重要组成部分。
儒琴今日英语俚语 （English Slang of the Day)
backseat driver
英语解释：
an annoying passenger in a car who keeps giving the driver advice how to drive；a person who is eager to advise without responsibility; someone who gives unwanted advice or who tries to control something that is supposed to be controlled by another person
中文解释
字面意思是“后座司机”， 指对驾驶员指手画脚的乘客; 汽车里招人烦的乘客，不停地跟司机叨叨叨该怎么开车。这个俚语更深层次意思是：引申为指手画脚的人；一个急于发表建议但不任何负责的人；试图控制本应由他人控制的事物的人
原文举例
Obama’s backseat drivers, John Kerry, Susan Rice, and Ben Rhodes, have lots of advice for Trump on Iran.
Indeed, the president’s Twitter account provides a fascinating archive of citizen Trump’s instinctive thoughts and feelings from the days before he occupied the Oval Office – and are a helpful reminder that it’s often easier to be a backseat driver than the one steering the car.
Perhaps what the prime minister had to report about the state of the American demands at the NAFTA table was so dire that none of those he briefed could see his or her interest in claiming the role of backseat driver.
奥巴马“指手画脚的人”约翰·克里(John Kerry)、苏珊·赖斯(Susan Rice)和本·罗兹(Ben Rhodes)对特朗普在伊朗问题上有很多建议。
的确，总统的Twitter账户提供了一个精彩的档案，记录了美国公民特朗普在入主椭圆形办公室之前的本能想法和感受——并帮助提醒人们，作为普通公民指手画脚往往比实际在位更容易。
或许，（加拿大）总理不得不汇报在北美自由贸易协定(NAFTA)谈判桌上有关美国要求的情况。美国提出的要求是如此紧迫严重，以至于他所汇报的那些人都看不出他或她有兴趣给总理充当发表建议但不负责人的人。
