attached to, inseparable, entangled
繾 centers on being closely tied or tangled together: attached, inseparable, or entangled in a way that is hard to undo.
繾 combines 糸 (thread) with 遣, which likely contributes the sound and the idea of sending or connecting. The character suggests threads that are tied or entangled.
The left side is thread 糸, and the right side 遣 suggests sending or connecting. Picture threads being sent together and becoming tangled, so they are attached and inseparable.
For ケン, imagine a tangled knot of threads that you cannot undo: the knot is a ken (a range of knowledge) of entanglement, and ken -> ケン.