"Non-outgassing minor planet" is a description, of course, but the word used by scientists and other people familiar with the subject matter is asteroid.  Beyond this, just because a description is accurate doesn't mean it's good - "non-sandwich" or "non-elephant" would obvious be correct descriptors, but would also be horribly misleading.  It's your own conclusion "non-outgassing minor planet" is a good or appropriate descriptor.  This could even be true (it's not - whether or not an object is currently active is not the distinction being drawn in the literature, of course), but it's still your own opinion, and hijacking Wikipedia to publish your own opinions is still not appropriate. D 
"Hijacking Wikipedia"? Seriously?
But thank you for finally actually responding. "Non-elephant" is vague, whereas "non-outgassing" (arguably better rephrased to "not known to be outgassing") is a specific (non-vague) term used to refer to a characteristic, so your comparison does not hold. The problem with parrotting specific words for specific instances is that it creates a non-uniformity in the meaning of the words, and hence creates unnecessary ambiguity and unnecessarily decreases clarity. Now, "asteroid" has always been a word without an exact definition, but has come to be increasingly referred to those minor planets out to the orbit of Jupiter, see asteroid. This is also the agreed-upon use on Wikipedia. Other minor planets have also occasionally been referred to as "asteroid", especially those that were discovered early, such as 944 Hidalgo (the first minor planet discovered with a semi-major axis beyond Jupiter's), and "asteroid" is sometimes also used to include all minor planets, including e.g. all Kuiper-belt objects. It is not OR to avoid referring to these as asteroids; OR refers to the actual content, not the specific terms used (nor the specific punctuation of terms, see e.g. this discussion). Moreover, this term is easily avoided by using more-specific and better-defined words, which increases the informative value to our readers anyway.