quirk
Definitions
A peculiar behavioral habit or mannerism.
A sudden twist, turn, or unexpected occurrence.
A strange or unusual aspect of something.
Examples
His most endearing quirk is that he hums while he reads.
Every machine has its own little quirk that you have to learn to work around.
It was a strange quirk of fate that they ended up in the same city after all these years.
Synonyms
idiosyncrasy peculiarity eccentricity foible mannerism oddity quirkiness
Antonyms
normality standard conformity regularity commonality uniformity convention