to perform an action whose effects will be negligible in comparison to broader forces at work, and will be difficult or impossible to accurately measure, as in “We don’t need to send someone to Times Square to shill for Hamilton,1 that’s like watering the grass in a thunderstorm”; used to highlight the futility of a proposed course of action and dissuade the hearer from further considering it; the length2 and obscure intent of this phrase conspire to render it exceedingly rare in actual usage, as jargon users tend to favor more jocund terms used in backslapping fashion

  1. For those reading this at some remove from the United States and/or the year 2016, this is a Broadway play whose rapturous reception and breakout influence in wider society have created a pop culture juggernaut. ↩
  2. Despite its apparent unwieldiness, this phrase is by chance in perfect dactylic trimeter, which does lend it a bit of poetic elegance. ↩