This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 楲 is uncertain. It combines 木 (tree/wood) with 威, but the original semantic and phonetic roles are unclear.
With 木 (tree) on the left and 威 (authority/majesty) on the right, you might imagine a wooden tool or vessel associated with dignity, but the actual meaning is obscure.
For イ, picture an eagle (イーグル) perched on a wooden branch: eagle -> イ, and the tree 木 stands beside the majestic 威.