n.
   - soft fibres accumulated in small light clumps. ▸the fur or feathers of a young mammal or bird. 
- trivial or superficial entertainment or writing.
- informal a mistake, especially in speech, sport, or music.
v.
  - 
(usu. fluff something up)
 make (something) fuller and softer by shaking or patting it.
- informal fail to accomplish (something) properly.
Etymology
  C18: prob. a dial. alt. of C16 flue ‘down, nap, fluff’, appar. from Flemish vluwe.