1570s, from un-(1) "not" + kempt "well-combed, neat," from variant past participle of Middle English kemben "to comb," from Old English cemban "to comb," from Proto-Germanic *kambijan, from *kamb- "comb" (see comb, n.). Form unkembed is recorded from late 14c. The verb kemb is rare after 1400s, but its negative past participle form endures.