Source : Webster's Revised Unabridged Dictionary (1913)

Downright \Down"right`\, a.
   1. Plain; direct; unceremonious; blunt; positive; as, he
      spoke in his downright way.

            A man of plain, downright character.  --Sir W.
                                                  Scott.

   2. Open; artless; undisguised; absolute; unmixed; as,
      downright atheism.

            The downright impossibilities charged upon it.
                                                  --South.

            Gloomy fancies which in her amounted to downright
            insanity.                             --Prescott.
      -- {Down"right`ly}, adv. -- {Down"right`ness}, n.

Downright \Down"right`\, adv.
   1. Straight down; perpendicularly.

   2. In plain terms; without ceremony.

            We shall chide downright, if I longer stay. --Shak.

   3. Without delay; at once; completely. [Obs.]

            She fell downright into a fit.        --Arbuthnot.

Source : WordNet®

downright
     adv : thoroughgoing; "he is outright dishonest"

downright
     adj 1: characterized by plain blunt honesty; "a downright answer";
            "a downright kind of person"
     2: complete and without restriction or qualification; sometimes
        used informally as intensifiers; "absolute freedom"; "an
        absolute dimwit"; "a downright lie"; "out-and-out mayhem";
        "an out-and-out lie"; "a rank outsider"; "many right-down
        vices"; "got the job through sheer persistence"; "sheer
        stupidity" [syn: {absolute}, {out-and-out(a)}, {rank(a)},
        {right-down}, {sheer(a)}]