Opacos

Opacos is the masculine plural adjective in Spanish that describes something that does not permit light to pass through or that lacks transparency. The feminine plural is opacas, the singular masculine is opaco, and the singular feminine is opaca. In everyday language, opaco can refer to surfaces, materials, or tones that obscure vision or reflectivity. Metaphorically, it can describe ideas or explanations that are unclear or difficult to understand, or people who are not forthcoming.

Etymology: The term derives from Latin opacus, from opacare “to shade,” related to opacitas (opacity).

Usage in science and everyday life: In optics and materials science, an opaco material absorbs or scatters light, appearing dull or nontransparent; examples include metals, pigments, and many polymers. In radiology and medicine, the related noun opacity (opacidad) is used to describe areas on an X-ray or CT that appear more opaque than normal, such as lung opacities or lens opacities in the eye. In architecture and design, opaco surfaces obscure vision or diffusion and are often chosen to provide privacy or control the amount of light entering a space.

Other notes: The term opaco can also describe non-physical ways something is unclear, such as an opaca argument or reasoning, indicating a lack of transparency or straightforwardness. Related terms include opacidad (opacity), transparente (transparent), and translúcido (translucent).