Into a state of increasing panic, agitation, or desperation, especially as may lead to failure, decline, or stagnation. In aviation, a "flat spin" refers to the motion of an aircraft that has spun out of control. It seems like we're entering into a flat spin as a society, with the amount of hatred and distrust everyone seems to be aiming at one another. The country's economy went into a flat spin when its real estate market crashed a couple years ago.