humanitarian, do-gooder, improver -- (someone devoted to the promotion of human welfare and to social reforms)
humanist, humanitarian -- (an advocate of the principles of humanism; someone concerned with the interests and welfare of humans)
Overview of adj humanitarian
The adj humanitarian has 2 senses
human-centered, human-centred, humanist, humanistic, humanitarian -- (marked by humanistic values and devotion to human welfare; "a humane physician"; "released the prisoner for humanitarian reasons"; "respect and humanistic regard for all members of our species")
humanitarian -- (of or relating to or characteristic of humanitarianism; "humanitarian aid")