idiosyncrasy

In hay fever certain patients present a peculiar idiosyncrasy, often inherited, almost always neuroarthritic.

What reveals perhaps more distinctly than anything else Chopin's idiosyncrasy is his friendship for Titus Woyciechowski.

He had a constitutional dislike for falsehoods, which was perhaps not so much a virtue as an idiosyncrasy.

They chatted volubly over this idiosyncrasy, and even laughed at it, but quite decorously so that our feelings might be spared.

This very singular idiosyncrasy he attributed to a fright when he was an infant in the arms of his nurse.