# all the best of Assyria's men

This identifies who the word "them" refers to.

# she made herself unclean with everyone she lusted for—and with all their idols

"she made herself unclean by sleeping with everyone she lusted for and by worshiping all their idols"

# unclean

A person who God considers spiritually unacceptable or defiled is spoken of as if the person were physically unclean.