* If you're thinking about the study of word origins: The opposite could be neology, the study of new words and their creation.
* If you're thinking about tracing words back to their roots: The opposite could be deconstruction, which focuses on breaking down words into their constituent parts and analyzing their meaning in context, rather than tracing their historical development.
* If you're thinking about the historical evolution of words: The opposite could be semantics, the study of meaning in language, which focuses on how words are used and understood in the present.
In essence, the "opposite" of etymology depends on the specific aspect you are interested in.