Yes, I believe the term performance enhancing is defined properly in regards to sports. In sports performance enhancing applies to drugs that athlete stake t improve their on field performance. The abbreviation is PED's and they have been used by numerous athletes to break records from the Olympics to the MLB, that would other wise not be broken without them.
I think that the term "performance enhancing" is used properly among sports. Things such as steroids allow one to build an abnormal, and unfair, amount of muscle. A lot of sports depend on strength and agility, and therefore the addition of extra muscle can be seen as enhancing the performance of an athlete.
Performance enhancing is far too broad a term. Technically, both exercise and proper diet are performance enhancing, as someone that does both of those will perform better than someone who doesn't. The term needs another word for clarification, such as "Illegal" or "unauthorized" to clarify what the term means and whether or not the "enhancing" should be allowed.
Sports are inaccurate in the end when it comes to performance enhancing, and this is not different when we are talking about terms. Performance enhancement is such a grey area that people refuse to consider - not everything that is a chemical is an evil substance, and there are so many levels to consider.
It would be more appropriate to call it body altering than performance enhancing. The enhancement of an individuals performance is thought of as a good thing if they do it properly. This suggest that if someone said performance enhancing is a certain context it could be confused with taking these drugs.