an odd or remarkably unusual person, thing, or event.

the quality of being odd; singularity, strangeness, or eccentricity.

an odd characteristic or trait; peculiarity.

noun

convention , habit , norm , normality , regularity , standard , usualness

noun

anomaly , bizarreness , characteristic , conversation piece , curiosity , eccentricity , extraordinariness , freak , freakishness , idiosyncrasy , incongruity , irregularity , kink , oddness , outlandishness , peculiarity , phenomenon , queerness , quirk , rarity , singularity , strangeness , unconventionality , unnaturalness , original , abnormality , marvel , nondescript , wonder