The Collaborative International Dictionary of English v.0.48:

Flexible \Flex"i*ble\, a. [L. flexibilis: cf. F. flexible.]
   1. Capable of being flexed or bent; admitting of being
      turned, bowed, or twisted, without breaking; pliable;
      yielding to pressure; not stiff or brittle.
      [1913 Webster]

            When the splitting wind
            Makes flexible the knees of knotted oaks. --Shak.
      [1913 Webster]

   2. Willing or ready to yield to the influence of others; not
      invincibly rigid or obstinate; tractable; manageable;
      ductile; easy and compliant; wavering.
      [1913 Webster]

            Phocion was a man of great severity, and no ways
            flexible to the will of the people.   --Bacon.
      [1913 Webster]

            Women are soft, mild, pitiful, and flexible. --Shak.
      [1913 Webster]

   3. Capable or being adapted or molded; plastic,; as, a
      flexible language.
      [1913 Webster]

            This was a principle more flexible to their purpose.
                                                  --Rogers.

   Syn: Pliant; pliable; supple; tractable; manageable; ductile;
        obsequious; inconstant; wavering. -- Flex"i*ble*ness,
        n. -- Flex"i*bly, adv.
        [1913 Webster]

WordNet (r) 3.0 (2006):

flexibly
    adv 1: with flexibility; "`Come whenever you are free,' he said
           flexibly" [ant: inflexibly]