Why skivvies is slang for underwear is a little unclear, however, it was originally considered nautical slang.  An earlier skivvy/skivey was also used in London as a slang word for a “female domestic servant.”

In Iran, “female domestic servant” is slang for “wife.”

The word “buddy” may come from an alteration of the word brother, or from British slang, “butty” (companion).  “Butty” is a variant of booty, in the phrase booty fellow (one who shares plunder).

man 1: Hey, you mind if I invite my booty fellow to come watch the game with us?

man 2: Sure… I’ll give you guys the couch.

The slang phrase “going postal,” as in getting uncontrollably furious and violent, derives from tragic incidents involving United States Postal Service workers. Between 1986 and 1997, more than 40 people were murdered by spree killers in over 20 acts of workplace violence.  You know what hasn’t murdered 40 people?  E-mail.