Unlike

a.
  1. Not like; dissimilar; diverse; having no resemblance; as, the cases are unlike.
  2. Not likely; improbable; unlikely.
    3. Unlike quantities (Math.),
    quantities expressed by letters which are different or of different powers, as a, b, c, a2, a3, xn, and the like.
    Unlike signs (Math.),
    the signs plus (+) and minus (-).