Plonker Share definition Flag 1.Somebody who is a bit...simple to say the least. 2.A game played between men with their genataila A: You're a bit of a twat, aren't you? B: Shut up you plonker! You can barely tell your arse from your elbow! Plonker by anonymous February 13, 2022 0 0 Get merch Get the Plonker mug. Buy Now — $32.95 See more merch