unlike (adj.)

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.)

c. 1300, "unevenly," from un- (1) "not" + like (adv.) (see like (adj.)). From 1590s as "in a manner differing."