What sort of improvement ?

As I lay awake in bed early this morning after a miserable two days with a heavy cold, I realised gratefully that some of the worst symptoms had eased. I knew I would be asked ‘how I was’ sooner or later, so imagined myself explaining that there had been a considerable improvement from the situation as it was yesterday – until the thoughtful but surprisingly wakeful pedant in me interrupted: “Hey ! Wait a moment ! You can’t ‘improve from’. Shouldn’t you ‘improve on’? And why that string of long-winded Latinate terms ?” So I decided to reword the news of my recovery: “I’m much better”, I would say, using four syllables rather than twenty-four.

The word ‘improve’ (first found in the English language in the sixteenth century) is not what it seems: its second element is not (in spite of some authorities) our E ‘prove’, from the Latin verb probo implying to ‘declare after a test that something is sound’, to ‘recommend from experience’. Nor (as you might guess) has it anything to do with ‘improvident’ or ‘improvisation’ (both from Latin pro + video/vis-- = to see).

The best explanation of the word is that it is derived from Norman French emprouer (= to be profitable), the ‘prou’ part of which probably evolved from one or other of three Latin verbs: prodeo/prodit-- = to move forward, advance (intransitive); proficio/-fect--= to cause to advance, gain advantage or be profitable; or produco/product-- = to bring forward, cultivate or lengthen (from which we get our E terms ‘produce’ and ‘product’and the Fr produit). The Old French prou might have derived, via Late Latin, from any of these: funny things did happen to Late Latin words, especially slang usages, as they evolved into Old or regional French. What seems very likely is that the origin of ‘improve’ lies in the world of commerce or the concept of investment.

What sort of improvement ?