This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
偂 combines 亻 (person) with 前, but the exact historical development and original meaning are uncertain.
A person 亻 standing before 前 something, but the intended meaning is unclear.
For セン, imagine a person 亻 advancing forward 前 with a sense of urgency: the sound セン echoes the idea of moving ahead.