Definitions of dark:

• noun:   an unenlightened state

  Example: "He was in the dark concerning their intentions"

• noun:   absence of light or illumination
• noun:   an unilluminated area

  Example: "He moved off into the darkness"

• noun:   the time after sunset and before sunrise while it is dark outside
• noun:   absence of moral or spiritual values

  Example: "The powers of darkness"

• adjective:   secret

  Example: "Keep it dark"

• adjective:   not giving performances; closed

  Example: "The theater is dark on Mondays"

• adjective:   brunet (used of hair or skin or eyes)

  Example: "Dark eyes"

• adjective:   devoid or partially devoid of light or brightness; shadowed or black or somber-colored

  Example: "Sitting in a dark corner"

• adjective:   (used of color) having a dark hue

  Example: "Dark green"

• adjective:   marked by difficulty of style or expression

  Example: "Much that was dark is now quite clear to me"

• adjective:   showing a brooding ill humor

  Example: "A dark scowl"

• adjective:   causing dejection

  Example: "The dark days of the war"

• adjective:   lacking enlightenment or knowledge or culture

  Example: "The dark ages"

• adjective:   stemming from evil characteristics or forces; wicked or dishonorable

  Example: "Darth Vader of the dark side"

• adjective:   having skin rich in melanin pigments

  Example: "The dark races"

• name:  A surname (rare: 1 in 100000 families; popularity rank in the U.S.: #9044)