Possible meanings are 1) "Do not behave as the world behaves" or 2) "Do not think the way the world does." (See: [[rc://en/ta/man/translate/figs-metaphor]])
# Do not be conformed
Possible meanings are 1) "Do not let the world tell you what to do and think" or 2) "Do not allow yourself to act and do what the world does." (See: [[rc://en/ta/man/translate/figs-activepassive]])
# this world
This refers to unbelievers who live in the world. (See: [[rc://en/ta/man/translate/figs-metonymy]])
You can translate this in an active form. Alternate translation: "but let God change the way you think and behave" (See: [[rc://en/ta/man/translate/figs-activepassive]])