wander about, walk around, revolve
躚 centers on aimless or circular movement: wandering about, walking around, or revolving. The meanings share the idea of motion without a fixed destination.
躚 combines 足 (foot) with 遷 (move, shift), suggesting movement on foot. The exact historical development is uncertain, but the phono-semantic structure is plausible.
The foot radical 足 beside 遷 (which suggests moving or shifting) paints a picture of feet that keep moving without a clear goal: wandering, walking around, or revolving.
For セン, imagine a person wandering in circles, tracing the shape of the sen (千, one thousand) strokes of a giant calligraphy brush: 千 -> セン, and the endless walking matches the revolving motion.