ancient musical instrument
敫 refers to an ancient musical instrument. Its exact nature is obscure, and it has no clear modern meaning beyond this historical reference.
The historical origin of 敫 is uncertain. It likely combines 攵 (action hand) with a phonetic element, but the exact development is unclear.
The right side 攵 suggests an action, and the left side 白 over 方 might be seen as a white square drum being struck. Imagine an ancient musician striking a white square drum with a stick.
For セク, imagine the ancient instrument making a sharp 'seku' sound when struck. The sound 'seku' cues セク.