plainly

Concise Oxford English Dictionary © 2008 Oxford University Press:
plain1

▶adjective

• 1 not decorated or elaborate; simple or ordinary.

  ■ without a pattern; in only one colour.

  ■ unmarked; without identification: a plain envelope.

• 2 easy to perceive or understand; clear.

  ■ not using concealment or deception; frank: he recalled her plain speaking.

• 3 (of a person) having no pretensions; not remarkable or special.

  ■ (of a woman or girl) not marked by any particular beauty; ordinary-looking.

• 4 sheer; simple (used for emphasis).

• 5 (of a knitting stitch) made by putting the needle through the front of the stitch from left to right. Compare with purl1.

▶adverb informal

• 1 used for emphasis: that's just plain stupid.

• 2 clearly; unequivocally.

▶noun a large area of flat land with few trees.

– derivatives
plainly adverb,
plainness noun.

– origin ME: from OFr. plain, from L. planus, from a base meaning ‘flat’.

Concise Oxford English Dictionary © 2008 Oxford University Press:
plain2

▶verb archaic

• 1 mourn; lament.

• 2 complain.

– origin ME: from OFr. plaindre, from L. plangere ‘to lament’.