Definitions:

1. A characteristic, trait, or feature that is distinctive or unusual, often making something or someone stand out from others. NOUN
   • The peculiarity of the plant's leaves, which seemed to glow in the dark, perplexed botanists.
2. Refers to a particular quality, behavior, or aspect that sets apart an individual, object, or situation NOUN
   • The habit of humming to herself while working was just one of her many peculiarities that endeared her to her coworkers.

Synonyms:

• abnormality
• distinctive feature
• distinguishing characteristic
• eccentricity
• Oddity
• rarity
• specialty
• strange
• unique