This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
圽 combines 土 (earth) with 勿, but the historical development and original meaning are uncertain.
The left side is earth 土 and the right side is 勿, a shape often associated with negation or a bound object. Without a clear meaning, picture something buried in the earth that should not be disturbed.
For ボツ, imagine a buried object suddenly popping up with a 'bots!' sound: bots -> ボツ, as the earth 土 shifts around the 勿 shape.