investi

The seam is Latin's, not Esperanto's. Investi looks as though it might be en- plus vesti (to dress), and the history says you are right: Latin investire genuinely was in- plus vestire, to clothe somebody in something. But that cut was made in Latin, the halves fused there, and Esperanto imported the finished word as the single root invest-. Try to split it in Esperanto and the pieces do not work: the prefix is en-, not in-, and envesti is not a word. It belongs with inspiri, konsterni and reklamo in the class where knowing the Latin helps your memory and gives you no rule you can reuse.

How the clothes became the money. A bishop or a magistrate was robed at the ceremony that gave him his office, so investire came to mean installing somebody in a position - English still says invest with authority, and investiture is the ceremony. Renaissance Italian banking borrowed the metaphor for putting capital into a venture: the money is clothed in the enterprise. The financial sense arrived in English in about 1600 and it is the sense Esperanto has.

Using it. Investi ion en io or en ion both occur: with the accusative when you are thinking of movement into the venture, without when you are thinking of where the money now sits. Investo is an investment, investanto an investor, investaĵo the asset itself, and malinvesti to divest. It takes non-financial objects freely, as English does: investi tempon, investi laboron, investi esperon en la projekton.

Neighbours to keep apart. Ŝpari is to save, to hold money back. Investi is to put it to work. Negoco is the business or the deal, profito what comes back, and risko what you accepted to get it.