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plain; simple; subdued; sober
reserved (behaviour, attitude, etc.); modest; quiet; unobtrusive
quite; a (little) bit
「地味」 has another reading with different meanings.
彼女は派手な色より地味な服装を好む。
She prefers plain clothes.
地味な作業だがとても重要だ。
It's plain work but very important.
地味でも確実な方法を選んだ。
I chose a plain but reliable method.