The Collaborative International Dictionary of English v.0.48:

Checker \Check"er\ (ch[e^]k"[~e]r), v. t. [imp. & p. p.
   Checkered (ch[e^]k"[~e]rd); p. pr. & vb. n. Checkering.]
   [From OF. eschequier a chessboard, F. ['e]chiquier. See
   Check, n., and cf. 3d Checker.]
   1. To mark with small squares like a checkerboard, as by
      crossing stripes of different colors.
      [1913 Webster]

   2. To variegate or diversify with different qualities,
      colors, scenes, or events; esp., to subject to frequent
      alternations of prosperity and adversity.
      [1913 Webster]

            Our minds are, as it were, checkered with truth and
            falsehood.                            --Addison.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Checkered \Check"ered\ (ch[e^]k"[~e]rd), a.
   1. Marked with alternate squares or checks of different color
      or material.
      [1913 Webster]

            Dancing in the checkered shade.       --Milton.
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   2. Diversified or variegated in a marked manner, as in
      appearance, character, circumstances, etc.; as, a
      character with a checkered past
      [1913 Webster]

            This checkered narrative.             --Macaulay.
      [1913 Webster]

WordNet (r) 3.0 (2006):

checkered
    adj 1: patterned with alternating squares of color [syn:
           checked, checkered, chequered]
    2: marked by changeable fortune; "a checkered business career"

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "checkered":
   able to adapt, adaptable, adjustable, alterable, alterative,
   changeable, check, checked, ever-changing, flexible, fluid,
   impermanent, kaleidoscopic, malleable, many-sided, metamorphic,
   mobile, modifiable, mosaic, movable, mutable, nonuniform,
   permutable, plaid, plastic, protean, proteiform, resilient,
   rubbery, supple, tessellate, tessellated, transient, transitory,
   variable