The Collaborative International Dictionary of English v.0.48:

Lawless \Law"less\, a.
   1. Contrary to, or unauthorized by, law; illegal; as, a
      lawless claim.
      [1913 Webster]

            He needs no indirect nor lawless course. --Shak.
      [1913 Webster]

   2. Not subject to, or restrained by, the law of morality or
      of society; as, lawless men or behavior.
      [1913 Webster]

   3. Not subject to the laws of nature; uncontrolled.
      [1913 Webster]

            Or, meteorlike, flame lawless through the void.
                                                  --Pope.
      -- Law"less*ly, adv. -- Law"less*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

lawlessly
    adv 1: in an illegal manner; "they dumped the waste illegally"
           [syn: illegally, illicitly, lawlessly] [ant:
           lawfully, legitimately, licitly]