Are modern humans classed as “gracile” or “robust”?
Several people seem to have confused “robust” with “robustus” (i.e. Paranthropus robustus). This is not what the question is referring to. When referring to skeletal anatomy, the word “robust” tends to be used to refer to characteristics like relative thickness of bones, deepness of muscle markings (can also be described as “rugosity”) and overall size of the skeleton. So, for example, it can be said that relative to modern humans, Neanderthals were a very robust species. In answer to the question, you could say that relative to other hominid species preceeding Homo sapiens, we are indeed “gracile”. However it’s important to remember that there’s a lot of variation within our species and as such there exist individuals whose skeletons may be considered “robust” when considered next to an “average” skeleton from a modern human.