Well, we all know what unkempt is, right? All messy, shirt untucked, hair to and fro – not well-kept-up. And we know that unkempt is one of those odd negative words that don’t have a positive version, so it’s always funny to say kempt because you’re using a word that’s not a word because English is kinda unkempt in that it has words like dishevelled and discombobulated and disgruntled that don’t have positives.
But of course there is a word kempt. It’s just not used much. Especially not in its original sense.
You’d have to comb a dictionary for it, but if you look you’ll see that kempt is the past tense of a verb. Now, we know that kept is the past tense of keep. But there is no keemp. No, this is more in the line of dreamt. The present tense verb – no longer used now except in some dialects – is kemb.
And what is kemb? It’s a verb that has been supplanted by a related verbed noun. Kembing is something you do with something. That something you do it with – also from the same original root – is a comb.
So yes, you kemb your hair with a comb, and if you have done so, it is kempt. But kemb gained extended senses – ‘make smooth or elegant’ (OED), for one. So something that is kempt is something that is well presentable. And something that is unkempt is… not.
(Kemb is – was – also used to refer specifically to combing wool. And a woman who did this as her line of work was a kempster. Which looks to modern eyes like a word for someone who, by being tidy and kempt and so on, is a sort of opposite of a hipster.)
Here’s one more thing to think about: How kempt is your pronunciation? And how kempt do you even want it to be? When you say kempt – or unkempt – do you really say the [p]? It’s easily inserted between the [m] and the [t], since it has the place of the former (lips) and the voicing and manner of the latter (voiceless stop). But it is also easily dropped. And when you say unkempt, do you really say [n] before the [k]? Place assimilation often draws it towards the [k] so it becomes a [ŋ]. And the preceding vowel is nasalized and sounds the same regardless of where the next consonant is, so you may not even notice the difference.
Or at least not until you hear it said overly scrupulously. Record yourself saying unkempt normally in a casual environment. Then record yourself saying it precisely, with the n as [n] and the [p] present. That sure does sound more precise and kempt, doesn’t it? But I bet it doesn’t put you at ease. It’s possible to be too kempt.