unlike (adj.) Look up unlike at Dictionary.com
c. 1200, "not resembling," from un- (1) "not" + like (adj.). Similar formation in Old English ungelic, Old Frisian unlik, Old Norse ulikr, Middle Danish ulige, German ungleich.
unlike (adv.) Look up unlike at Dictionary.com
c. 1300, "unevenly," from un- (1) "not" + like (adv.) (see like (adj.)). From 1590s as "in a manner differing."