loose, lenient
綽 centers on a state of being relaxed or not tightly constrained: loose in fit, lenient in attitude, or easygoing in manner.
綽 combines 糸 (thread) with 卓, which likely contributes the sound. The idea of loose thread may have led to the meanings of looseness and leniency.
The left side is thread 糸, and the right side 卓 looks like a table. Picture a thread loosely draped over a table, not pulled tight—it's loose and lenient.
For シャク, imagine a loose thread that you shake off the table: shake -> シャク, and the thread falls loosely away.