The story
- Middle English · inherited fromflykke“light blow or stroke”
- English todayflick
From Middle English flykke (“light blow or stroke”). Later uses apparently interpreted as a back-formation from flicker. The use of flick to mean a film or movie derives from the fact that early films had a low frame rate, thus causing the film to "flick" rapidly when projected onto a screen.
Etymology from Wiktionary, CC BY-SA 4.0.