The Collaborative International Dictionary of English v.0.48:

Submissive \Sub*mis"sive\, a.
   1. Inclined or ready to submit; acknowledging one's
      inferiority; yielding; obedient; humble.
      [1913 Webster]

            Not at his feet submissive in distress,
            Creature so fair his reconcilement seeking.
                                                  --Milton.
      [1913 Webster]

   2. Showing a readiness to submit; expressing submission; as,
      a submissive demeanor.
      [1913 Webster]

            With a submissive step I hasted down. --Prior.
      [1913 Webster]

   Syn: Obedient; compliant; yielding; obsequious; subservient;
        humble; modest; passive.
        [1913 Webster] -- Sub*mis"sive*ly, adv. --
        Sub*mis"sive*ness, n.
        [1913 Webster]

WordNet (r) 3.0 (2006):

submissively
    adv 1: in a servile manner; "he always acts so deferentially
           around his supervisor" [syn: deferentially,
           submissively]