This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development is uncertain. The modern form visually contains 足 (foot) and 今, but the original component relationship is unclear.
With 足 (foot) and 今 (now), imagine a foot that is unsteady right now, wobbling and stumbling.
For チン, picture a chin wobbling unsteadily as someone stumbles: chin -> チン, and the foot 足 is unsteady.