The Collaborative International Dictionary of English v.0.48:

Scheme \Scheme\, v. t. [imp. & p. p. Schemed; p. pr. & vb. n.
   Scheming.]
   To make a scheme of; to plan; to design; to project; to plot.
   [1913 Webster]

         That wickedness which schemed, and executed, his
         destruction.                             --G. Stuart.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Scheming \Schem"ing\, a.
   Given to forming schemes; artful; intriguing. --
   Schem"ing*ly, adv.
   [1913 Webster]

WordNet (r) 3.0 (2006):

scheming
    adj 1: used of persons; "the most calculating and selfish men in
           the community" [syn: calculating, calculative,
           conniving, scheming, shrewd]
    2: concealing crafty designs for advancing your own interest; "a
       selfish and designing nation obsessed with the dark schemes
       of European intrigue"- W.Churchill; "a scheming wife"; "a
       scheming gold digger" [syn: designing, scheming]

Moby Thesaurus II by Grady Ward, 1.0:

127 Moby Thesaurus words for "scheming":
   Byzantine, Machiavellian, Machiavellic, acute, arch, artful,
   artifice, astute, cabal, cagey, calculating, canny, chiseling,
   clever, collusion, collusive, complicity, complot, confederacy,
   connivance, connivent, conniving, conspiracy, conspiring,
   contrivance, contriving, counterplot, covin, covinous, crafty,
   cunning, cute, deceitful, deep, deep-laid, deep-laid plot,
   designing, devious, diplomatic, disingenuous, duplicitous,
   engineering, false, falsehearted, feline, finagling, finesse,
   forsworn, foxy, frame-up, fraudulent, furtive, game, guileful,
   indirect, ingenious, insidious, insincere, intrigue, intriguing,
   inventive, knowing, little game, machination, maneuvering,
   manipulation, nefarious, packed deal, packed jury, pawky, perjured,
   planning, plot, plotting, politic, prearrangement,
   preconcertedness, premeditation, preordering, put-up job, ready,
   resourceful, rigged jury, rigging, scheme, schemery, serpentine,
   setup, sharp, shifty, shrewd, slick, slippery, sly, smooth, snaky,
   sneaky, sophistical, stacked deck, stealthy, stratagem,
   stratagemical, strategic, subtile, subtle, supple, surreptitious,
   tactical, treacherous, trick, trickish, tricksy, tricky, two-faced,
   uncandid, underhand, underhanded, underplot, unfrank, unsincere,
   untruthful, up to, vulpine, wary, web of intrigue, wily,
   wire-pulling