A male or female who is secretly having multiple affairs, that are unkown to everyone else. The only people that know of the secret are also underground whores that are involved in the affair with another underground whore.
*Donald decides to pry and look at some Katie's diary that contains personal information regarding her skanky love life that would be unknown of otherwise* Donald's response is: "Damn this bitch is an underground whore!"
by KBiscuit April 16, 2011
Get the underground whoremug.