The Collaborative International Dictionary of English v.0.48:

Freely \Free"ly\, adv. [AS. fre['o]lice.]
   In a free manner; without restraint or compulsion;
   abundantly; gratuitously.
   [1913 Webster]

         Of every tree of the garden thou mayst freely eat.
                                                  --Gen. ii. 16.
   [1913 Webster]

         Freely ye have received, freely give.    --Matt. x. 8.
   [1913 Webster]

         Freely they stood who stood, and fell who fell.
                                                  --Milton.
   [1913 Webster]

         Freely we serve
         Because we freely love.                  --Milton.

   Syn: Independently; voluntarily; spontaneously;
        unconditionally; unobstructedly; willingly; readily;
        liberally; generously; bounteously; munificently;
        bountifully; abundantly; largely; copiously;
        plentifully; plenteously.
        [1913 Webster]

WordNet (r) 3.0 (2006):

freely
    adv 1: in a free manner; "the painting featured freely brushed
           strokes"

Moby Thesaurus II by Grady Ward, 1.0:

54 Moby Thesaurus words for "freely":
   abundantly, amply, bigheartedly, bounteously, bountifully,
   by choice, candidly, cleanly, easily, electively, frankly, free,
   freehandedly, freeheartedly, generously, graciously, gratuitously,
   greatheartedly, handsomely, hospitably, independently,
   largeheartedly, lavishly, liberally, munificently, openhandedly,
   openheartedly, openly, optionally, outright, plainly, plentifully,
   profusely, readily, smoothly, spontaneously, unceremoniously,
   unconstrainedly, ungrudgingly, unreservedly, unrestrainedly,
   unselfishly, unsparingly, unstintingly, voluntarily, willfully,
   willingly, with abandon, with both hands, with open hands,
   without coercion, without reserve, without restraint,
   without stint