As you've no doubt noticed, the meaning of words change with the passage of time.
An example is the word nice. Nice used to be an insult and meant foolish or stupid in the 13th century and it went through many changes right through to the 18th century with meanings like wanton, extravagant, elegant, strange, modest, thin, and shy or coy. Now it means a good, or pleasing or thoughtful, or kind.
Silly meant blessed or happy in the 11th century and went through pious, innocent, harmless, pitiable and feeble minded before ending up as foolish or stupid.
Pretty started as crafty this changed to clever or skillfully made, then to fine and ended up as beautiful. [Etymologies cited above taken from here: Etymology- How Words Change Over Time]
And consider the word "Charedi." Once upon a time this word was used to refer to someone who was "Afraid of Heaven." Now, it means afraid, period.
Afraid of the future, afraid of the past, afraid of technology, afraid to explore, afraid to think, afraid of women's issues , afraid of the neighbors, etc, etc.
Updated: December 24, 2006