This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
偙 combines 亻 (person) with 帝, which likely contributes a sound element. The exact historical development is uncertain.
A person 亻 beside 帝, but the meaning is unclear. Imagine a person standing before an emperor, perhaps in distress or excellence, but the true sense is lost.
For テイ, picture a person 亻 taking tea テイ with the emperor 帝: tea -> テイ.