1. A freak of nature; an unusual or abnormal occurrence or product.
Usage: Latin origin; formal or literary; Often used in scientific or philosophical contexts
2. A playful or sportive action; a jest or joke.
Usage: archaic; rare in modern usage

Examples

• The two-headed calf was considered a lusus naturae by the local farmers.
• Scientists studied the lusus as evidence of genetic mutation.
• The painting's distorted perspective was a deliberate lusus, not an error.
• In medieval times, unusual births were often attributed to divine lusus.
• The architect's whimsical tower was a lusus that delighted visitors.