plain as day
*plain as dayand *plain as a pikestaff
1. Cliché very plain and simple. (*Also: as ~.) Although his face was as plain as day, his smile made him look interesting and friendly. Fred: I have a suspicion that Marcia is upset with me. Alan: A suspicion? Come on, Fred, that's been plain as a pikestaff for quite some time! 2. and *plain as the nose On one's face Cliché clear and understandable. (*Also: as ~.) The lecture was as plain as day. No one had to ask questions. Jane: I don't understand why Professor Potter has been so friendly this week. Alan: It's plain as the nose on your face. He wants to be nominated for Professor of the Year.
(as) plain as day
easy to see or understand The secret to our success is as plain as day - make a good plan and stick to it. I looked at the list and there, plain as day, was my name on the list of winners.Opposite of: (as) clear as mud
plain as day
Also, plain as the nose on your face. Very obvious, quite clear, as in It's plain as day that they must sell their house before they can buy another, or It's plain as the nose on your face that she's lying. These similes have largely replaced the earlier plain as a packstaff or pikestaff, from the mid-1500s, alluding to the stick on which a peddler carried his wares over his shoulder. The first term, from the late 1800s, is probably a shortening of plain as the sun at midday; the variant dates from the late 1600s.