Zombie

A zombie is an undead corpse, typically devoid of a soul and with no free will, originating from Voodoo beliefs. In the Fallout world, the term generally refers to ghouls, who very much resemble the zombies of pre-War horror films, often as a derogatory remark. Also used to describe feral ghouls.

Examples of use
The first appearance of the word in Fallout was when it was used by Set's ghoul gangsters to refer to themselves, and was pejoratively used towards Children of the Cathedral cultists. However their were rumors of both the ghouls and their origins circulating prior to 2161.

In Fallout 2, the Chosen One can call Wooz a zombie, which appears to deeply offend him.

In Fallout 3, most ghouls are very offended by the term. It is commonly used by the bigots who live at Tenpenny Tower, especially the chief of security, Gustavo, who uses the disparaging term prolifically. Calling Roy Phillips or Mister Crowley a zombie may lead them to attack. Mister Crowley will hire the Lone Wanderer to kill supposed ghoul bigots by shooting them in the head like they do in old zombie movies.

In Fallout: New Vegas, the term zombie isn't used as frequently as in Fallout 3, but the player character does use the term to insult and threaten Grecks into paying back caps owed to Francine Garret  and Raul Tejada uses the word zombie when referring to a nickname of his.