"a person who seeks to correct social ills in an idealistic, but usually impractical or superficial, way," 1654 (as
do-good), in "Zootomia, or Observations on the Present Manners of the English: Briefly Anatomizing the Living by the Dead. With An Usefull Detection of the Mountebanks of Both Sexes," written by Richard Whitlock, a medical doctor. Probably used even then with a taint of impractical idealism. Modern pejorative use seems to have begun on the socialist left, mocking those who were unwilling to take a hard line. OED has this citation, from "The Nation" in 1923:
"There is nothing the matter with the United States except ... the parlor socialists, up-lifters, and do-goods."
The form
do-gooder appears in Amer.Eng. from 1927, presumably because
do-good was no longer felt as sufficiently noun-like. A slightly older word for this was
goo-goo.
[doo-goo
d-er, -goo
