uncembed

Old English cemban meant 'to comb,' from camb (a comb). The past participle cembed meant 'combed.' Adding the negative prefix un- produced uncembed—uncombed, disordered, not groomed. The word was straightforward: unkempt hair was hair that had not met a comb.

Over the centuries, cemban disappeared from everyday English, replaced by the simpler 'comb' (from the same Germanic root). But its negative form survived. Unkempt persisted in Middle English as unkempt while the positive form—kempt, meaning 'combed' or 'neat'—gradually faded from common use.

This created an oddity in English: a word whose opposite barely exists. You can be unkempt, but saying someone is 'kempt' sounds strange, almost humorous. The word exists in dictionaries (Merriam-Webster lists kempt as an adjective meaning 'neatly kept') but it reads as a back-formation—a word reconstructed from its own negation.

The pattern is not unique. English has several 'unpaired negatives'—words like uncouth (couth is rare), disheveled (sheveled is nonexistent), and disgruntled (gruntled exists only as a joke). These words survived because the negative state was more common, or more interesting, than the positive one.