plain-Jane

[pleyn-jeyn]

adjective Informal.

simple and modest; unadorned; basic: a plain-Jane car dressed up with leather upholstery.

Origin of plain-Jane

First recorded in 1935–40

noun Informal.

First recorded in 1910–15

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

The Daily Pic: Fluorescent tubes as plain-Jane art supplies.
Dan Flavin Enlightened Us
Blake Gopnik
February 28, 2013

"unattractive woman," first attested 1912.