Yes, I understand that language is always changing. Yes, I understand that the English-speaking nations do not have the equivalent of l’Académie française. Nevertheless, I take umbrage at certain terms for which meaning has been literally turned on its head.
Decimate is one of those terms.
It comes from the lovely practice of the Roman legions where they would line up those Roman soldiers who had deserted or otherwise engaged in some other serious misbehavior, and kill every tenth one of them as punishment. Deci = 10. We see this in decimal and dozens of other words in English which derive from the Latin root.
Destroying ten percent of a military group was enough for everyone to get the idea without doing away with a large number of trained military personnel. Roman soldiers weren’t individuals, after all, they were fully owned by Rome. Decimation was a way of punishing, but without doing too much damage to a unit.
However, in today’s usage, “to decimate” means “to destroy utterly or completely, to cripple beyond one’s ability to recover, etc.” In short, it is more in keeping with annihilation than decimation.
The next time you wish to say that someone completely destroyed someone else (in a political or sporting sense, since that seems to be where decimate is most commonly abused) let’s go with something a bit more accurate, like “destroyed” or “gravely injured” or perhaps even “massively damaged.”