n. A person who performs short-term missionary work, particularly as part of a vacation.
His accusations, now pouring forth with considerable force, were directed at the naive "vacationaries" spending millions of dollars traveling to his country, creating a welfare economy that deprives people of the pride of their own accomplishments.
—Robert D. Lupton, “Toxic Charity,” HarperOne, October 11, 2011
Not long ago, the families of Fairfax Presbyterian Church spent thousands of dollars to fly their teens to Mexico for eight days of doing good. They helped build homes and refurbish churches as part of an army of more than 1 million mostly Christians who annually go on short-term international mission trips to work and evangelize in poverty-stricken lands….

Critics scornfully call such trips "religious tourism" undertaken by "vacationaries."
—Jacqueline L. Salmon, “Churches Retool Mission Trips,” The Washington Post, July 05, 2008
2006 (earliest)
Judd Birdsall, former managing editor of The Review of Faith & International Affairs, a Christian journal, grew up in Japan in an evangelical missionary home. Too often these days, he says, untrained short-term missioners — or "vacationaries" — offend indigenous populations and undermine hard-earned relationships cultivated by long-term missionaries over many years.
—G. Jeffrey MacDonald, “On a mission — a short-term mission,” USA Today, June 18, 2006
Huzzahs to Will Ames for spying this term.