plain Definition

plain
adj

1. All of one colour; unpatterned; undecorated.
2. Simple; unsophisticated; without improvement, embellishment or pretensions.

Example: plain food
Example: not Dr or Professor, just plain Mr
Thesaurus: modest, ordinary, simple, common, conventional, unadorned, unostentatious, unpretentious, everyday; Antonym: ostentatious, elaborate.
3. Obvious; clear.

Thesaurus: obvious, manifest, clear, understandable, apparent, evident, patent, lucid, legible; Antonym: unclear, abstruse.
4. Straightforward; direct.

Example: plain language
Example: plain dealing
Thesaurus: candid, forthright, artless, blunt, frank, abrupt, outspoken, bluff, rude.
5. Frank; open.
6. Said of a person: lacking beauty.

Thesaurus: homely (US), ugly, unattractive.
7. Sheer; downright.

Example: plain selfishness

noun

1. A large area of relatively smooth flat land without significant hills or valleys.

Thesaurus: prairie, grassland, steppe, plateau, flat, mesa, heath.
2. knitting.
The simpler of two basic stitches, with the wool passed round the front of the needle. See also purl.

adverb

1. Utterly; quite.

Example: just plain stupid

Derivative: plainly
adverb

Derivative: plainness
noun

Idiom: plain as a pikestaff

All too obvious.

Etymology: 13c: French, from Latin planus level.