fleeting, fickle
儚 centers on the transient, unstable nature of things: something fleeting that passes quickly, or a fickle, changeable state that cannot be relied upon.
儚 combines the person radical 亻 with 夢 (dream), suggesting a person in a dream-like, insubstantial state. The exact historical development is uncertain, but the component relationship is clear.
A person 亻 beside a dream 夢: imagine someone whose thoughts are as fleeting and fickle as a dream, here one moment and gone the next.
For ボウ, picture a fleeting dream that vanishes like a bow (ボウ) being drawn and released—the arrow flies away in an instant, just like a fickle thought.