| Word | Definitions | Synonyms |
|---|---|---|
| opaque | (adjective) not transmitting or reflecting light or radiant energy; impenetrable to sight | - |
| (adjective) hard or impossible to understand | Synonyms: unintelligible | |
| radiopaque | (adjective) not transparent to X-rays or other forms of radiation | Synonyms: radio-opaque |
| semiopaque | (adjective) partially opaque | - |