>Not really the opposite. "RESTful", when it doesn't actually refer to Fielding's REST [0], generally doesn't mean anything, its just an empty buzzword being dropped into a product description that communicates no meaningful information at all.
Well, it instantly communicates: 1) over HTTP(S), 2) using HTTP queries (and verbs) 3) taking advantage of HTTP authentication, caching etc, 4) returning, more often that not, JSON.
That is, the important parts people care about.
Not really the opposite. "RESTful", when it doesn't actually refer to Fielding's REST [0], generally doesn't mean anything, its just an empty buzzword being dropped into a product description that communicates no meaningful information at all. Even then, its seems to be intended to communicate "conforming to the REST architectural style", it just fails to do so because its done without any knowledge of the REST architectural style (and not even with an consistent wrong view such that the use of the term could be said to have a particular definition different from that that Fielding laid out for REST.)
[0] Though, to be fair, it often does, although sometimes to only some particular part of it (and not always the same part) as opposed to systems that lack the part being focused on. This use is somewhat consistent with Fielding's, though it would probably be better to focus on naming the particular element.