flicker
     n 1: a momentary flash of light [syn: {spark}, {glint}]
     2: North American woodpecker
     3: the act of moving back and forth [syn: {waver}, {flutter}]
     v 1: move back and forth very rapidly; "the candle flickered"
          [syn: {waver}, {flitter}, {flutter}, {quiver}]
     2: shine unsteadily; "The candle flickered" [syn: {flick}]
     3: flash intermittently; "The lights flicked on and off" [syn:
        {flick}]
Source: WordNet® 2.0