Referring to an Object by a Part of its Name [I7]

How can I tell a player that referring to a specific object by a part of it’s name is not allowed? An example of when I wouldn’t want them to be able to do so:

>Examine car. You see nothing special about the car keys.

The annoying thing is that I think I saw how to do this somewhere recently, but I can’t find it anywhere. All help is greatly appreciated, as ever!

You can make the object privately-named and give the vocabulary explicitly, although unless you anticipate trouble with disambiguation when there’s a car in the same location it’s better not to remove vocabulary because some players will try to refer to them as “car” when there’s no ambiguity.

[code]The car keys are a privately-named thing. Understand “car keys” and “keys” as the car keys.
The garage is a room. The car keys are in the garage.

Test me with “x keys/x car keys/x car”.

Thanks for the tips!