Flicker
Old English flicorian, flycerian ‘to flutter’, probably of Germanic origin and related to Low German flickern and Dutch flikkeren .
wiktionary
From Middle English flikeren(“to flutter”), from Old English flicerian, flicorian(“to flutter”).
Akin to Saterland Frisian flikkerje(“to flicker”), West Frisian flikkerje(“to flicker”), Dutch flikkeren(“to flicker, flutter”), German Low German flickern(“to light up, flash, flicker”). Compare Old English flacor(“flickering, fluttering”), German flackern(“to flicker, flutter”), Old English flēoġan(“to fly”).
1808, American English, probably echoic of the bird's call, or from the white spotted plumage which appears to flicker.
flick + -er
etymonline
flicker (v.)
Old English flicorian "to flutter, flap quickly and lightly, move the wings," originally of birds. Onomatopoeic and suggestive of quick motion. Sense of "shine with a wavering light" is c. 1600, but not common till 19c. Related: Flickered; flickering.
flicker (n.1)
1849, "wavering, unsteady light or flame;" 1857 as "a flickering," from flicker (v.).
flicker (n.2)
type of North American woodpecker, 1808, American English, said to be echoic of bird's note, or from black spots on plumage of the underparts that seem to flicker as it flits from tree to tree.
