Fetching details from the dictionary...
colouring; coloring; shade of colour (color)
sex appeal (esp. of women); sexiness; sexual allure; seductiveness
interest in the opposite sex; sexual feelings; sexual urge
charm; elegance; romance; graciousness
feminine presence
desire; interest; ambition; inclination
彼女は大人の色気を感じさせる。
She gives off an adult sex appeal.
その俳優は年齢を重ねて色気が増した。
That actor has gained more charm with age.
派手ではないが、ほのかな色気が漂う服装だった。
It wasn't flashy, but the outfit carried a subtle allure.