[singular + singular or plural verb] (disapproving) those members of a political or other group whose views are considered to be very extreme and crazy极端分子；极端（或狂热）分子集团- They stressed that only the lunatic fringe of the movement was involved in the incident.他们强调，只有运动中的极端分子卷入了这一事件。
See also fringe | lunatic