A phrase that indicates something so obvious that even the thickest, most oblivious person should see it. Usually, but not always, meant in a slightly insulting or derogatory manner; Origins are unknown but possibly derived from Irish. Use of it seems to have started on the east coast but is also found throughout the country, mostly in rural communities. Similar to: "as plain as the nose on your face".
"Those kids died? Well it's a shame but it's plain-as-day they shouldn't have been playing at the top of the cliffs."
"Did I see the latest Darwin Award? Well it's plan-as-day that you shouldn't strap a rocket engine to the roof of your car."
"How do you get downtown? See that water tower, head for that and you'll find downtown, plain-as-day, just to the right."
by Goodbye_Charlie October 11, 2013
Get the plain-as-day mug.