stroll, rub

蹭 is composed of the radical 足 (foot) and 曾 (once). 足 represents walking or foot movement, while 曾—originally a pictograph of a multi-layered steamer pot—carries the sense of layering or repetition. Thus, 蹭 was initially used to depict pacing back and forth slowly in overlapping, repeated steps, which later extended to mean rubbing, chafing, or dragging one's feet against a surface.