1 plain /ˈpleɪn/ adjective
plainer; plainest
1 plain
plainer; plainest
Learner's definition of PLAIN
[also more plain; most plain]
: having no pattern or decoration
: not having any added or extra things
: easy to see or understand
: simple and honest
always used before a noun : complete and total
: not unusual or special in any way : ordinary
: not handsome or beautiful

in plain sight

chiefly US or in plain view
: in a place that is easily seen

plain clothes

: the ordinary clothes of a police officer who is not wearing a uniform
see also plainclothes

plain sailing

see sailing

— plainly


— plainness

noun [noncount]
2 plain /ˈpleɪn/ noun
plural plains
2 plain
plural plains
Learner's definition of PLAIN
: a large area of flat land without trees
3 plain /ˈpleɪn/ adverb
3 plain
Learner's definition of PLAIN
: truly or completely used to make a statement or description more forceful