This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 彅 is uncertain. It is a rare character composed of 弓 and 剪, but its origin and original meaning are unclear.
With no clear meaning, picture a bow (弓) being trimmed or cut (剪 suggests cutting) — perhaps a bow being shaped, but the true meaning is unknown.
For なぎ, imagine a calm (凪, なぎ) sea, and a bow (弓) floating on it: なぎ -> なぎ, though the connection is artificial.
—