The Collaborative International Dictionary of English v.0.48:

Indirectly \In`di*rect"ly\, adv.
   In an direct manner; not in a straight line or course; not in
   express terms; obliquely; not by direct means; hence,
   unfairly; wrongly.
   [1913 Webster]

         To tax it indirectly by taxing their expense. --A.
                                                  Smith.
   [1913 Webster]

         Your crown and kingdom indirectly held.  --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

indirectly
    adv 1: not in a forthright manner; "he answered very indirectly"
           [ant: directly, flat, straight]

Moby Thesaurus II by Grady Ward, 1.0:

29 Moby Thesaurus words for "indirectly":
   at an angle, by proxy, circlewise, circuitously, deceitfully,
   deviately, deviously, digressively, divagationally, divergently,
   excursively, fraudulently, furtively, guilefully, in behalf of,
   insidiously, obliquely, on one side, round about, shiftily,
   sideling, sidelong, sideways, sidewise, surreptitiously,
   to one side, treacherously, trickily, underhandedly