comply with, obey, shun, avoid
遹 centers on following a path or rule: complying with or obeying something, and by extension, shunning or avoiding what goes against that path.
遹 combines the movement radical 辶 with 矞, which likely contributes the sound. The exact historical development is uncertain, but the character is associated with following or complying.
The movement radical 辶 suggests a path, and the inner part 矞 looks like a complex rulebook. Picture walking along a path while carefully obeying the rules inside, and stepping aside to avoid anything that breaks them.
For イツ, imagine an itsy-bitsy rulebook inside 矞 that you must obey as you move along the path: itsy -> イツ.