to pierce, to break through
擉 centers on forceful penetration: piercing something or breaking through a barrier. Both given meanings share the idea of a sharp, directed action that overcomes resistance.
擉 combines 扌 (hand) with 蜀, which likely contributes the sound and may relate to piercing or breaking through. The exact historical development is uncertain.
The hand radical 扌 beside 蜀 suggests a hand driving something sharp forward. Picture a hand using a tool to pierce a tough surface and break through.
For サク, imagine piercing a sack with a sharp tool: sack -> サク, and the hand breaks through the fabric.