What is meant by "al-Khawass" (the select few) according to the Malikis in the context of the ruling on uncovering the thigh?

It is not permissible for a man to look at the 'awrah of another man, which is from the navel to the knee, according to the majority of scholars. An exception to this is the wife and the slave woman, as it is permissible for them to look at his 'awrah, just as it is permissible for him to look at theirs. As for the 'awrah of a man in relation to a non-mahram (definition) woman, it is everything except the face and extremities.