This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
栯 is a rare character combining 木 (tree) with 有. The exact historical development is uncertain, and no clear meaning is recorded in standard Japanese sources.
The left side is a tree 木, and the right side is 有 (possess). Without a clear meaning, you might imagine a tree that possesses something mysterious, but treat this as a placeholder.
For イク, imagine a tree that grows quickly, like an iku (行く, to go) motion upward: iku -> イク, but remember this is just a mnemonic hook.
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