"Green" as a term for "environmentally-friendly" is stupid. Green is a color. It's use to describe a philosophical/political/methodological concept stems, I suppose, from the fact that vegetation outside of winter and fall is often green, and vegetation is something that abounds especially in places where humans are not giving it undue suppression, is thus associated with preserving such places as well as the whole planet. Even though the whole planet is much more blue.
Tongue no longer in cheek, I don't like "green" as a concept other than a nice color because it is imprecise and very quickly made nonsensical. I'm nonetheless saddled with using it, since it is recognized as a marketing tool by the company I work for and is front-and-center in the descriptions of my department and my job title, and even the industry in which I work.
"Sustainable" and "Sustainability" is the more sophisticated term, embodying a more clear view of what the philosophy actually means, which is to consider how well said activity/object/policy can be carried out into the long-term with regard to the environment, recognizing that we care about the environment because of how interrelated it is to pretty much everything if you look at it hard enough and how much we depend on having a functioning environment, not only because in some places said environment is pretty and "pristine" (hah!) We can and do talk about "sustainability" as not meaning the environment: most frequently economic sustainability, but no-sleep college kid running off of ten cups of coffee also comes to mind. The idea is the same: short-term actions without regard to long-term consequences has the real potential to come back to bite you later.
"Sustainability" is recognized and understood by most people associated with environmentalism, yet may not obviously be so to those who are not. And I say that also makes it a preferable term, because the goal of sustainability is not to be a side pursuit for hippies, but to describe how society actually is. Able to keep going. With positive delta well being, even, not something degrading over time from overuse and lack of planning.