I tend to create various groups, styles, titles and genres for photographs that I take and I see...but mostly for my own photography.
It helps me to organize my thoughts and communicate with others when needed.
The word "romantic" in the title of this group of photographs indicates an affectionate idealistic point of view of the photographer towards the subject.
The basic difference between, for example, a "glamour nude portrait" and a "romantic nude portrait" (in my personal terminology) perhaps lays in styling and the chosen moments...while a glamour shot usually needs a rather attractive lighting and perfect styling and it is posed, a "romantic nude portrait" could be more about finding that special moment, connection, chemistry and mood which is not necessarily possible in a very structured setting.
The nudity is an important part of this concept, since I would rather to diffuse any dramatic effects from outside elements such as fashion, locations and similar things...but choosing the moment is the major key here...perhaps 90% of the whole thing...and you can't force it...you have to nurture it and try to appreciate it but with the least amount of intrusion and the maximum amount of attention to finding the right moment, setting the correct exposure for the situation and suitable framing and composition.
So it can become a matter of obsession, selectivity and dynamism between the subject and photographer....and it could become very rewarding as well.