n. A person who favors a project that would add a dangerous or unpleasant feature to his or her neighborhood.
Other Forms
Northern Virginia: I'm really impressed by Secretary Gates's actual decisions to cut unnecessary defense projects. The natural reaction is howls from the Senators and representatives from the affected areas. My question is, will any Senator (like a John McCain, say) be statesman enough to stand up in support of Gates, or will the yes-in-my-backyard (yimby) voices be the only ones heard from?
When is a NIMBY not a NIMBY?

When the NIMBY is actually a YIMBY — Yes In My Backyard.

The YIMBY movement in Toronto is considered a positive antidote to the negative image that stalks many neighbourhood activist and resident groups better known for what they oppose than the ideas they favour.
—Tess Kalinowski, “YIMBYists seek positive solutions,” The Toronto Star, February 14, 2009
1988 (earliest)
You know about NIMBY's, Not in My Back Yard. These are the opposite, YIMBY's, by all means Yes in that same plot of grass.
—“..And the Year of the YIMBY,” The Washington Post, February 19, 1988