If you think I have a large vocabulary, you are right. But despite my voracious reading I have never stumbled upon 'pot-valiant' until just now, in a piece by Mona Charen wherein I found the sentence, "And it's true that some Republicans, like Americans for Tax Reform's Grover Norquist, have fetishized their opposition to taxes to the point where they defend pot-valiantly even tax subsidies such as those for ethanol."
To be pot-valiant is to have the courage that comes from being drunk. Noah Webster puts it this way in his 1828 American Dictionary: "Courageous over the cup; heated to valor by strong drink." See here.
The reason I have a large vocabulary is because I rarely allow myself the luxury of skipping over words I don't know. With few exceptions I look them up and then write them down, either in my journal or on my calendar. Or I 'blog' them. It is no good merely to look them up. You must write them down and then re-read what you have written. Only then will they stick.
Trouble is, in a barely literate society of tweeting twits getting dumber by the minute, you will elicit incomprehension or worse from your fellow citizens if you put your vocabulary to use. Of course, catamite, louche, canaille, desuetude, animadversion, apotropaic and zetetic will be lost on them. But yours will be the pleasure of reading high-grade literature with comprehension.