indulge in, give free reign to
縱 centers on letting go of restraint: indulging desires, giving free rein to impulses, or allowing something to proceed without control.
縱 is the traditional form of modern 縦. It combines 糸 (thread) with 從 (follow), suggesting a thread that follows loosely, giving the idea of letting go or indulging. The exact historical development of the meaning is uncertain.
The left side 糸 is a thread, and the right side 從 looks like two people following. Imagine a thread that is not pulled tight, letting the people wander freely—indulging and giving free rein.
For ジュウ, imagine a jeweler indulging in loose threads of gold: jew -> ジュウ, and the thread 糸 is given free rein.