How is "opaque" best defined?

The term "opaque" is best defined as "not transparent, hard to understand." In various contexts, it refers to a physical characteristic where light does not pass through an object, making it impossible to see through, like a solid wall or a piece of frosted glass. Metaphorically, when something is described as opaque, it often signifies that it is not easily comprehensible, suggesting complexity or ambiguity that makes understanding difficult.

This definition aligns well with both literal and figurative uses of the term, which emphasizes the idea of lack of clarity or transparency in communication or concepts. Words or situations that are opaque often require further explanation or simplification to be understood effectively.

The other options, while they touch on aspects of clarity and interpretation, do not encapsulate the essence of what "opaque" means in its standard usage across different contexts. For instance, being "completely clear and understandable" or "somewhat clear but difficult to decipher" directly contradicts the core idea of opacity, which inherently involves a degree of obscurity or confusion.