flicker1
  
  v.
   - shine or burn unsteadily and fitfully.
 - (of a feeling) be briefly perceptible.
 - make small, quick movements.
 
n.
 an instance of flickering.
 
  Derivative
  
  Etymology
  OE flicorian, flycerian ‘to flutter’, prob. of Gmc origin.
 
  
    
flicker2
  
  n.
 an American woodpecker that often feeds on ants on the ground. 
[
Colaptes auratus (
common or 
northern flicker) and related species.]
 
  Etymology
  C19: imitative of its call.