block up, obstruct, stagnant
滯 centers on obstruction and lack of flow: something is blocked up, stagnant, or unable to move forward.
滯 combines 氵 (water) with 帶 (belt/sash), suggesting water that is held back or obstructed like a tied belt. The modern Japanese simplified form is 滞.
Water 氵 meets a belt 帶 tied tightly around it, blocking the flow. Picture a stream dammed by a sash, leaving the water stagnant and obstructed.
For タイ, imagine a tied belt blocking the water: tied -> タイ, and the water becomes stagnant.