My girlfriend and I have an ongoing game in which we try and use little used or unused roots words when a longer version of the word is common. For example, whelmed (underwhelmed or overwhelmed), peat (repeat), or juvenated (rejuvenated). So anyway, today I thought of “empt” as in preempt. When I talked to my girlfriend about it we both realized we had no clue what empt could possibly mean. I have no OED on hand and Google has turned up nothing, anyone know?
This might be overkill for your question (the short answer is “emere”, to buy or purchase), but it certainly answers it. 
Empt comes from the Latin verb “to buy, procure”, which is emo, emere, emi, emptum. The associated noun, “the act of buying” is emptio. Hence, in English, the verb to pre-empt: to acquire or appropriate something beforehand, and by extension, to anticipate something.
I forgot to add that the same root is evident in the well-know Latin phrase *caveat emptor *(“let the buyer beware”).
So that’s why consumerism leaves you with that empty feeling.
Oddly enough the word empty has no connection at all with the Latin emo, etc. It’s from an Old English word emetta, emetti meaning leisure. In fact the initial sense of the term in Old English, when used of persons, was “at leisure, not occupied or engaged. Also, unmarried”. When used of things it meant, as the modern word still does, unfilled.
While we’re at it on “leisure”, the Latin word for “leisure” is “otium”. “Negotium”, then, is what you’re involved in when you’re not relaxing, which is to say, work. Whence our word “Negotiate”.
Sometimes I tell my wife we need to combobulate something.
Sounds like it leaves both of you feeling gruntled.
Haha. That is one of our favorites. When one of use is feeling good we say we are combobulated.
Incidentally, such a formation (assuming it is not already a word, if obsolete) is called a retronym or back formation. I am feeling quite kempt today.
Can you “post-empt” something? :dubious:
For my own edification:
whelmed
Peat - Not a word (well…it’s moss, but that’s unrelated)
Juvenated - Also not a word (so far as I can tell)
The Word Detective often answers questions like this one. I remember him covering “whelmed” and “overwhelmed”, and I definitely recommend checking out his archives. He’s like a Cecil for words.
Yeah, I know that some of them aren’t actually words or that the non-prefixed meaning doesn’t really relate to the prefixed meaning, but it’s fun anyway. I mean surely if the word repeat means to do something again than to peat something should mean to do it the first time.
I’m failing to see the connection between exempt and the root. Anyone with the insight on this one?
ETA: Funny line from “An Officer and a Gentleman” which wasn’t kept in all versions of the film. The drill sergeant is explaining a grenade and says something like: “The grenade with the pin in it is inert. If you pull out the pin, it becomes ert.”
Roman Garage Sale Customer: is this old chariot for sale?
Roman Sampiro: No, it’s exempt.
Just thought of a new one. Somebody in the office was just talking about being in a wedding this weekend. So is the job of an usher to ush people?
If I recall correctly, Paddington the Bear was under that misapprehension in one of the original stories.