The word _bamboozle_ is still almost slang, though perhaps more common than it was two hundred years ago, when Swift attacked it. Even now we do not know where it came from. There was a slang word used at the time but now forgotten--_bam_, which meant a trick or practical joke; and some scholars have thought that _bamboozle_ (which, of course, means "to deceive") came from this. On the other hand, it may have been the other way about, and that the shorter word came from the longer. The word _bamboozle_ shows us how hard it is for meaningless slang to become good English even after a struggle of two hundred years.
We have seen how many slang words in English have become good English, so that people use with propriety expressions that would have seemed improper or vulgar fifty or ten or even five years ago. Other interesting words are some which are perfectly good English as now used, but which have been borrowed from other languages, and in those languages are or were mere slang. The word _bizarre_, which we borrowed from the French, and which means "curious," in a fantastic or half-savage way, is a perfectly dignified word in English; but it must have been a slang word at one time in French. It meant long ago in French "soldierly," and literally "bearded"--that is, if it came from the Spanish word _bizarra_, "beard."
Another word which we use in English has a much less dignified use in French. We can speak of the _calibre_ of a person, meaning the quality of his character or intellect; but in French the word _calibre_ is only in ordinary speech applied to things. To speak of a "person of a certain calibre" in French is very bad slang indeed.
Again, the word _fiasco_, which we borrowed from the Italian, and which means the complete failure of something from which we had hoped much, was at first slang in Italian. It was applied especially to the failure of a play in a theatre. To break down was _far fiasco_, which literally means "make a bottle." The phrase does not seem to have any very clear meaning, but at any rate it is far removed from the dignified word _fiasco_ as used in English.
The word _sack_ as used in describing the sack of a town in war is a picturesque and even poetic word; but as it comes from the French _sac_, meaning "pack" or "plunder," it is really a kind of slang.