flyweight

noun

1. A weight that moves outward depending on centrifugal force.
2. A weight class in many combat sports; e.g. in professional boxing of a maximum of 112 pounds or 50.8 kilograms.
3. (figuratively)Small, light or unimportant.

   “The characters of "Sex and the City 2" are flyweight bubbleheads living in a world which rarely requires three sentences in a row.”