to revile, to abuse
僝 centers on harsh verbal attack: reviling or abusing someone with words. The given meanings are narrow and do not suggest a broader conceptual cluster.
僝 combines 亻 (person) with 孱, which likely contributes the sound and may relate to weakness or inadequacy, but the exact historical development is uncertain.
A person 亻 beside 孱, a shape that suggests something weak or contemptible. Picture someone looking down on a weakling and reviling them.
For サン, imagine a person reviling someone under the hot sun: sun -> サン, and the harsh words sting like sunburn.