Opacus

Part of speech: adjective

Definitions

1. A term signifying an absence of transparency or clarity that often relates to a dark or cloudy appearance, resulting in something being difficult to see through or illuminated
2. The quality of being not clear or see-through, often appearing dim or shadowed
3. A property describing the inability of light to pass through, giving a dull or darkened look

Etymology: "Opacus" is the Latin adjective behind the English "opaque," and its history is largely a matter of Latin usage rather than a dramatic story. It meant "shady" or "shaded," describing ground or places sheltered from the sun, and it was used of thick foliage and dense shade. The word appears in classical Latin writers, where its sense was about being shaded rather than about light passing through glass or water. The English word "opaque" was borrowed directly from Latin "opacus" in the early 17th century, and it kept the original sense of blocking light. Its ancestry is often traced to an uncertain Indo-European root, but the more useful connection is to "umbra," the Latin word for shadow, which shares the same general idea of darkness and shelter from light.

Synonyms: opaque, cloudy, dark

Antonyms: transparent, clear, lucid