Smoothskin

Smoothskin (also smoothie) is a derogatory term that ghouls used to describe someone who is human, referring to the less ravaged outward appearance of humans compared to their own. The term can also be neutral,

Examples of use
In Fallout 3, the Lone Wanderer may ask Winthrop about the name upon entrance in Underworld, to which Winthrop will reply because the Lone Wanderer's skin is so smooth and "tasty". Winthrop will then laugh and say he was kidding, but "had you going, didn't I?" The Chosen One and Harold had a similar conversation in Fallout 2. Lumpy from Gecko also clarifies its usage around the time of 2241.

In Fallout: New Vegas, during the quest Come Fly With Me, a human called Chris Haversam refers to the Courier as smoothskin, even though he is a human himself. This is because he believes he is a ghoul. When fighting the ghouls at the REPCONN test site, Raul Tejada will refer to the Courier as a smoothskin when yells at the feral ghouls to "eat the smoothskin" instead of him.

Appearances
The term "Smoothskin" appears in Fallout 2, Fallout 3, Fallout: New Vegas, Fallout 4 and Fallout Tactics: Brotherhood of Steel.