Often, we think we know precisely what a word means as well as its proper usage, and yet when we actually take the time to look it up, or reference it someplace, we might find ourselves pleasantly surprised. What are some examples of fairly common words that were not exactly what they seemed?

I've just recently found out that wallow apparently means "take unrestrained delight in"; incongruous with the usual contexts in which I've heard the word dropped.

That is one of the meanings of the word, and they all sort of fit together.
I remember some years ago (more than I care to count) going to an uncle's farm on summer vacation.
It was a hot day, and watching his pigs in the mud gave me a fresh appreciation for the word "wallow" - and something of a desire to join them.
I find it interesting that perhaps the most common phrase we use the word in is "wallow in self-pity", but many of the people described thus are probably taking a kind of perverse delight in their predicament.