NIMBY (Not In My Back Yard) is an acronym for the opposition by people living in pleasant or rural areas to local construction of intrusive facilities, which are often intended primarily to serve people living far away: such as new roads or rail lines, power plants, waste storage facilities or the like, or intended to serve "undesirable" people locally, such as drug rehabilitation centers, halfway houses and the like. Such opposition typically comes from homeowners who fear that such developments will cause the resale value of their real estate to fall.
Generally people who express NIMBY sentiments acknowledge the need for the facilities, while arguing that they "just don't want them nearby to them". For example, most Americans agree that long distance electric power transmission lines are necessary, yet hardly anyone wants to live within sight of them - whether due to concerns for their safety or just because they look "ugly".
Some skyscraper aficionados use the term NIMBY for anyone who hates any kind of tall building or wants them torn down or restricted.
See also: drawbridge mentality, BANANA