This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
釮 combines 金 (metal) with 才, but the exact historical development and original meaning are uncertain.
The left side is metal 金 and the right side is 才, which can suggest talent or ability. Imagine a talented metalworker shaping a sharp blade, but remember the meaning is uncertain.
For セイ, picture a talented metalworker saying 'say' as they inspect their work: say -> セイ.