walk, move
躒 centers on physical movement, specifically walking or moving the body. The given meanings are closely related as basic actions of locomotion.
躒 combines 足 (foot) with 樂, which likely contributes the sound. The character is rare and its exact historical development is uncertain.
The left side is 足 (foot), and the right side 樂 suggests music or enjoyment. Picture a foot moving happily to music: walking and moving with rhythm.
For レキ, imagine a lucky foot that never gets tired: lucky -> レキ, and that foot keeps walking and moving.