Sinistrously /(sĭn"ĭs*trŭs*ly̆)/

Sin·is·trous·ly

Sinistrously

adv.
  1. In a sinistrous manner; perversely; wrongly; unluckily.
  2. With a tendency to use the left hand.
    Many, in their infancy, are sinistrously disposed, and divers continue all their life left-handed.