I like anomalous words that I haven't heard/read before and it's a personal priority of mine to make a mental note of and use any that I find, so it would be interesting to see what other people have come across.
Please provide a definition and/or a link to a definition of each word (if not we could probably just google it), and we can build a library, of sorts, for vocabulary to be used in everyday life or, say, English papers and the like.
I'll start, I suppose-
Composure or coolness shown in difficult or dangerous circumstances.
"He performed in front of millions with extraordinary sangfroid."