Which one of the following words is opposite in meaning to Opaque?

Transparent

The word that is opposite in meaning to Opaque is Transparent.

• Opaque means not transparent; not able to be seen through.
• Transparent means allowing light to pass through so that objects behind can be distinctly seen.

The other words, blur, hazy, and grimy, all mean something that is not clear or distinct. However, they are not the opposite of opaque because they can still be seen through, albeit not clearly.