respectful, mild, beautiful
穆 centers on a gentle, dignified beauty: a mild and respectful manner that is pleasing to behold.
穆 combines 禾 (grain) with 㣎, a component associated with fine, delicate ornamentation. Together they suggest the gentle beauty of ripening grain, extended to mildness and respect.
The left side is grain 禾, and the right side 㣎 looks like delicate hanging strands. Imagine a field of grain swaying gently in the breeze, a beautiful and mild scene that commands quiet respect.
For ボク, picture a respectful bow (お辞儀) in a field of grain: bow -> ボウ, and the respectful gesture cues ボク.