flicker

(noun) a momentary flash of light. Synonyms: spark, glint.

(noun) North American woodpecker.

(noun) the act of moving back and forth. Synonyms: waver, flutter.

(verb) move back and forth very rapidly. Synonyms: waver, flitter, flutter, quiver. Examples: "The candle flickered."

(verb) shine unsteadily. Synonyms: flick. Examples: "The candle flickered."

(verb) flash intermittently. Synonyms: flick. Examples: "The lights flicked on and off."