opaque
/əʊˈpeɪk/adjective
Not allowing light to pass through, so you cannot see through it.
Example sentences
- “The bathroom window is made of opaque glass.”
- “Store the medicine in an opaque bottle away from sunlight.”
- “Opaque curtains keep the bedroom dark during the day.”
The opposite is 'transparent'; 'translucent' lets some light through. Figuratively, opaque writing or rules are hard to understand.