Unlike \Un*like"\, a. 1. Not like; dissimilar; diverse; having no resemblance; as, the cases are unlike. 2. Not likely; improbable; unlikely. [Obsoles.] {Unlike quantities} (Math.), quantities expressed by letters which are different or of different powers, as a, b, c, a^{2}, a^{3}, x^{n}, and the like. {Unlike signs} (Math.), the signs plus (+) and minus (-).