adjective

• lacking in liveliness or animation
  "he was so dull at parties"
• emitting or reflecting very little light
  "a dull glow"
• not keenly felt
  "a dull throbbing"
• not having a sharp edge or point
  "the knife was too dull to be of any use"

adjective satellite

• being or made softer or less loud or clear
  "the dull boom of distant breaking waves"
• so lacking in interest as to cause mental weariness; ; ; ; ; ; - Edmund Burke; ; - Mark Twain
  "a boring evening with uninteresting people"
• (of color) very low in saturation; highly diluted
  "dull greens and blues"
• slow to learn or understand; lacking intellectual acuity; ; ; - Thackeray
  "so dense he never understands anything I say to him"