The English language is as fluid as it is complex. Made of a huge amalgamation of plenty of other languages both living and dead, sounds, spellings, and meanings are prone to constantly changing that means that words you use nowadays most of the time have a totally different original meaning. While the changes are usually harmless, oftentimes said words, simple gestures, or even nursery rhymes that are now tame used to mean something slightly more sinister… or vice versa.
While the word in used to describe Hannibal Lecter and the Joker, villain was first used to describe household waitstaff. Villain was a servant at a villa the rich associated being a servant being with being poor and being poor with crime, ergo the term evolved to mean an evil character.
As you know, bulldozers are one of the most easily recognizable pieces of heavy construction equipment as well as a favorite plastic toy of children. The name actually came from Civil War era racists who would go around with bull whips and beat up freed black slaves for trying to vote.
Today, being a blue-blood means you come from a noble or well-respected family. The original meaning though is a tad more racist. In 15th century Spain, Castilians saw having the look of sangre azul the bluish veins that show underneath pale skin as a way to prove their superiority over the darker-skinned countryman.
Whether youre familiar with the name Caduceus or not, you would probably be able to recognize this symbol of the modern medical community a winged staff entwined with two snakes. Ironically, that is actually the symbol of Mercury, the Roman god of Thieves (it was probably mistaken for the rod of Asclepius, the Greek god of healing and medicine.)