1. A combat situation in which an attacker, normally equipped with a superior weapons system, is presented with a large number of highly desireable, poorly defended and high-value targets all at once, such a situation might be an attack helecopter with night vision capability finding a complete enemy brigade or divisional HQ convoy stalled at night on a narrow road with no place to go and no air defence.
2. A workplace, bar, party or other place of entertainment where a new arrival finds a large number of attractive, unattached members of the opposite sex, and is spoilt for choice.
"God, I was in the pub last night and this hen party wandered in.... a dozen pissedgirls looking for fun... that's what I call a target rich environment !"
A situation that would normally fit the word "surrounded", however the party that is surrounded has some form of superior weapons system that would not have an issue with defeating all attacking parties at once, turning an undesirable situation into an environment rich with potential targets- hence the term, 'target-rich environment'.
Also occasionally used sarcastically to refer to being in a firefight or otherwise surrounded by hostile forces.
"This ain't an ambush, we have a goddamn tank- it's a target-rich environment. Fire at will."
(If used sarcastically) "I really don't care about the mission, I'm just trying to get out of this target-rich environment before some jackass blows my head clean off."
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi