Language Of Confusion: Acting!, Part IV

Continuing on our journey of words descended from the Proto Indo European root ag-, to drive, draw out, or move. These ones have a G in them, but not ag-.
 
First, we just did navigate, so I’m not going to go into all the details again, but it showed up in the late sixteenth century, about fifty years after navigation. The navi- is from nau-, the Proto Indo European word for boat, and the rest is from ag-, to drive out or move. To navigate is to drive a boat.
 
Next, for something completely different, is prodigy, which showed up in the mid fifteenth century meaning a portent, not meaning a person until the seventeenth century. It’s from the Old French prodige and classical Latin prodigium, prodigy or portent. The pro- means forth or before, and the -igium is thought to be from agere, to act. “To act before” makes sense for a portent, but it’s a little more confusing when in reference to a person.
 
And there’s ambiguity, which showed up in the fifteenth century, while ambiguous showed up about a century later. Both are from the Old French ambiguite and classical Latin ambiguitatem, which is just ambiguity, from the verb ambigere, to surround. Ambi- is from ambhi-, around, and the rest is from agere, meaning ambiguous is to act around. Okay, this one’s totally lost on me.
 
If you want a word that doesn’t even have an A in it, there’s cogent, which showed up in the mid seventeenth century from the French cogent. That’s from the classical Latin cogentem, compelling, from the verb cogere, to force or literally to drive together. See, the com- means together, and the rest is from agere, which also means to drive. Driving something together makes it cogent. Somehow.
 
Finally today, a very old word: synagogue. It showed up in English in the late twelfth century, from the Old French sinagoge, Late Latin synagogal, and Greek synagoge. The syn- is a prefix that actually means together, and the rest is from agein, to put in motion, from ag-. A synagogue is to drive together, as in an assembly. It’s also not the Hebrew word for synagogue, just the Greek loan-translation of the actual word used. And now it’s the English word for a Jewish house of assembly.
 
Sources
Online Etymology Dictionary
Google Translate
Omniglot
University of Texas at Austin Linguistic Research Center
University of Texas at San Antonio’s page on Proto Indo European language
Orbis Latinus