| Word | Definitions | Synonyms |
|---|---|---|
| opalescent | (adjective) having a play of lustrous rainbow colors | Synonyms: iridescent, nacreous, opaline, pearlescent |
| opaline | (adjective) having a play of lustrous rainbow colors | Synonyms: iridescent, nacreous, opalescent, pearlescent |
| opaque | (adjective) not transmitting or reflecting light or radiant energy; impenetrable to sight | - |
| (adjective) hard or impossible to understand | Synonyms: unintelligible |