wave, brandish, modest, humble
撝 centers on a hand gesture that can express either outward motion (waving, brandishing) or inward restraint (modesty, humility). The two meaning clusters are connected by the idea of a hand signal that communicates an attitude.
撝 combines 扌 (hand) with 爲, which likely contributes the sound and the idea of doing or acting. The exact historical development of the meaning split between waving and modesty is uncertain.
The hand radical 扌 beside 爲 suggests a hand making a gesture. Picture a hand waving to show off, or a hand held down humbly to show modesty—both are hand signals.
For キ, imagine a humble person holding a key (キー) in their hand, modestly offering it forward: key -> キ, and the hand gesture shows humility.