Asperity - n [L. asperitas, from asper, rough]1. Roughness of surface; unevenness; opposed to smoothness
2. Roughness of sound; that quality which grates the ear; harshness of
3. Roughness to the taste; sourness
4. Roughness or ruggedness of temper; moroseness; sourness; crabbedness
Now here's a word you can use in a myriad of contexts. The range of application is in the very definition of it - three of the five senses are listed. That's highly unusual for a word, at least as far as I've discovered. Most words go with other words. The context and association are built in already and it's strange to hear them used outside of that box. Not so with asperity. It has engrained versatility, which makes it great fun to use.
I couldn't find a single lick of history about this word aside from the little "L. asperitas, from asper, rough]" that's noted in the dictionary entry. But that doesn't count. The wide expanse of the web was also devoid of any passages, literary or otherwise, from famous folks who'd used it in ages past. I can't find it in me to be disappointed though. It's a very useable word.
It doesn't sound like something out of a Medieval castle or ancient text. It's pronouncable (which is always helpful). It's meaning can be explained quickly. And it can easily be incorporated into normal conversation without plastering a sign that says "I Am A Wordaholic" on one's forehead. Personally, I like wordaholics. Most wordaholics are either voracious readers, writers, or both and that means we have common ground. I understand, though, that an excessive love of abnormal vocabulary can be tedious for more normal people. That's why words like asperity were invented ;) They're bridge words. Wordaholics like using them and non-wordaholics don't mind hearing them.
And now to use it in a story...
"He was altogether out of place.
He almost appeared out of time.
His attire was most unusual. And he kept stealing glances over his shoulder and down the hallways, as if he was looking for someone. Or perhaps something. I followed him through the crowded parlor and into the antechamber, replying with the very minimum of courtesty to those who spoke to me as I passed. I saw him start down the stairs and slipped my shoes off, leaving my heels where their clack could not betray my presence.
It was so quiet below. All the lively sounds of the main rooms were muted, hushed enough to cover the movement of my gown as I stepped, but not loud enough to give life to the empty floor I soon reached. Where could he have vanished to? I took a few quick steps and peered down the hall that stretched out beneath the right wing of the house. It was empty. Lit and lovely, but empty. I dropped my skirts and turned to go back.
"Why do you follow me, madam?"
I caught my heart as it leapt to my throat at the drop of his voice.
He was leaning against the wall opposite me. Where had he come from?
"Truly, I find it most perplexing."
I swallowed, glad for strong, safe feeling of the wall at my back. "I meant no harm or insult, sir" I said. "I was only curious."
My voice sounded so frail and timid after his.
There was an asperity in his laugh that matched the rest his appearance. The uneven lines of hair on his face. The grating sound that girded his voice. The sharp cast of his face.
"I would warn you against curiosty, my lady," he said.
"I'm afraid I do not understand your meaning."
He came toward me. "Pray that you never do."
Then he took my hand, raised it to his lips, and walked away without another word.
"Wait, who are you?" I called after him.
He kept walking.