Possible meanings are 1) not standing in the judgment is a metonym for being judged by God and having to leave his presence. Alternate translation: "will not continue to stay before God when he judges them" or "will have to leave God's presence when he judges them as guilty" or 2) not standing in the judgment is a metaphor for being condemned in the judgment. "Alternate translation: "will be condemned in the judgment" or "will be condemned when God judges them" (See: [[rc://en/ta/man/jit/figs-metaphor]])
The noun judgment can be expressed as a verb. This probably refers to the final judgment when God judges all people. Alternate translation: "when God judges everyone"
Translators can supply the verb "stand." Alternate translation: "neither will sinners stand in the assembly of the righteous" or "and sinners will not stand in the assembly of the righteous" (See: [[rc://en/ta/man/jit/figs-ellipsis]])
Being accepted by God as righteous is spoken of as standing with the group of righteous people. Alternate translation: "and God will not accept sinners along with the righteous people" (See: [[rc://en/ta/man/jit/figs-metonymy]])