While flipping through The Economist's year end review yesterday in the coach [it was stuffed into the back of my overnight bag], I chanced upon an interesting article on the English language hitting its millionth word this April [approximately speaking]. In that article I made the interesting discovery that in the phrase "don't give a dam" dam refers to the Indian dam, which is still the word used colloquially for cost/price in Hindi/Urdu e.g. Iska dam kya hai? [What is the cost of this?] Kitna dam lagaya ? [how much have you priced this at] At some point in its usage, it got converted to the expletive damn. Here is a dam from the time of Emperor Akbar [NDIA, MOGHUL, Akbar, 1556-1605, copper dam, Val-81, 1001 AH (1592)] Do you know any other such instances of a word mutating in meaning like this?