To what extent can a wife look at the immodestly dressed women whom the Prophet (peace and blessings of Allah be upon him) described as "clothed yet naked"?

It is permissible for a Muslim woman to look at a non-Muslim woman—except for what is between the navel and the knee—when there is no lust and no fear of temptation. This is the relied-upon opinion due to the absence of the reason mentioned concerning the non-Muslim woman, which is that she might describe her beauty to a non-Muslim man.