Appearance:
* Dull: This is the most straightforward opposite, referring to a lack of luster or shine.
* Matte: This implies a surface that doesn't reflect light, creating a flat, non-reflective finish.
* Rough: This describes a surface that is uneven and doesn't reflect light evenly.
* Tarnished: This refers to a surface that has lost its shine due to oxidation or wear.
Figurative meaning:
* Drab: This describes something that is dull and uninteresting, lacking in sparkle or excitement.
* Boring: Similar to drab, this describes something that is lacking in stimulation or excitement.
* Unremarkable: This describes something that is ordinary and not noteworthy, lacking any special qualities.
Other:
* Hidden: This could be used if you're talking about something that was once shiny but is now covered or concealed.
The best opposite for "shiny" depends on the specific meaning you want to convey.