unsatisfactory
鍖 centers on a state of being unsatisfactory or falling short of expectations. The single given meaning is narrow, so treat it as a rare character whose core idea is simply 'unsatisfactory'.
鍖 combines 金 (metal) with 甚, which likely contributes the sound. The exact historical development is uncertain, and the modern form may be a simplification or variant.
The metal 金 on the left and 甚 on the right can be seen as a metal object that is 'extreme' (甚) in its poor quality, making it unsatisfactory.
For チン, imagine a metal object that is so unsatisfactory it makes a dull 'chin' sound when struck, like a cheap gong: chin -> チン.