(1) Does aconservative language better preserve its roots? (for example, Romanian is said to have best preserved its Latin roots due to being geographically surrounded by countries with non-Romance languages).
(2) Or does conservative refer to the slowness of innovation in modern structures, or to the resistance to change?
(3) I was also tempted to think that maybe it refers to resistance to influences from other languages,that is, when a language will try to find a new word of its own, rather than borrowing a ready one from a different language.