not fancy or decorated
said of a fabric: without a pattern
consisting of a single colour
a plain white shirt
flat or smooth
free of added substances; pure
plain water
unobstructed
in plain view
unmarked; with no identification
a plain envelope
obvious; easy to understand; unambiguous
was plain that he didn't want to go
free from deceitfulness or subtlety; candid
plain speaking
lacking special distinction; simple or ordinary
a plain country girl
plain home cooking
said of a person: not particularly attractive
I have known several Jacks, and they all, without exception, were more than usually plain — Oscar Wilde
said of knitting: done in rows of knit stitches
used for emphasis: utter; absolute
just plain stupidity
plainly adv
plainness noun
[Middle English via French from Latin planus flat, plain]