to stride over, to step across
躐 centers on moving across or beyond something in a single long step: striding over an obstacle or stepping across a boundary.
躐 combines 足 (foot) with 巤, which likely contributes the sound and may relate to stepping or crossing. The exact historical development of 巤 is uncertain.
The left side 足 means foot, and the right side 巤 looks like a complex barrier with hair-like strokes on top. Imagine a foot striding over a tangled hurdle.
For リョウ, picture a long-legged athlete named Ryo striding over a hurdle: Ryo -> リョウ, and his foot clears the barrier.