sinistrously

from The Collaborative International Dictionary of English v.0.48

Sinistrously \Sin"is*trous*ly\ (s[i^]n"[i^]s*tr[u^]s*l[y^]),
   adv.
   1. In a sinistrous manner; perversely; wrongly; unluckily.
      [1913 Webster]

   2. With a tendency to use the left hand.
      [1913 Webster]

            Many, in their infancy, are sinistrously disposed,
            and divers continue all their life left-handed.
                                                  --Sir T.
                                                  Browne.
      [1913 Webster]