Giving heterodox doctrines a bit of what-for
Literally: destroy – wicked / injustice – express / reveal – correct / justice
Alternately: The Buddhist concept of breaking down that which is wrong, bad, or untrue, and making the truth clear, or upholding that which is right. While I’m sure we can all think of cases where this is broadly needed in our secular lives, the phrase carries a connotation of defeating heresies and upholding the orthodox, “correct” ways of thinking and doing.
As one might expect, this phrase comes to us from a (late 6th century CE) Buddhist text: the 『三論玄義』 (Japanese Sanron gengi), one of the works on which the “emptiness” school of Buddhist thought was based.
正 may also be pronounced sei, although this is less common.
*(Post title spelling is correct, probably.)