King James Version
Because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened.English Standard Version
For although they knew God, they did not honor him as God or give thanks to him, but they became futile in their thinking, and their foolish hearts were darkened.Catholic Public Domain Version
For although they had known God, they did not glorify God, nor give thanks. Instead, they became weakened in their thoughts, and their foolish heart was obscured