The word itself means a bunch of things.
To me if a technology allows you to ignore i.e does not forcibly or otherwise expose you to the bits of it that you don't need it is not over-engineered.
OTOH Exhibit 1 of overengineered tech IMO are languages that force you to define a class in order to write "hello world"
I have always perceived XML as a scalable rather than over-engineered technology as the only concept it forces on you is well-formedness and every syntax has some grammar rules.
I prefer it to under-engineered technologies where you have to start importing libraries to handle basic everyday features like parsing delimited files, or regex.
