meaningless

Without the decryption key, the coded message is just a string of meaningless symbols.

(Chinese) 没有解密密钥，加密的消息只是一串无意义的符号。

The promise of a promotion felt meaningless after he saw the company's financial reports.

(Chinese) 在看到公司的财务报告后，晋升的承诺显得毫无意义。