1.Definition: (of business) not active or brisk
"Business is dull (or slow)"
2.Definition: (of color) very low in saturation; highly diluted
"Dull greens and blues"
3.Definition: being or made softer or less loud or clear
"The dull boom of distant breaking waves"
4.Definition: blunted in responsiveness or sensibility
"A dull gaze", "So exhausted she was dull to what went on about her"
5.Definition: darkened with overcast
"A dull sky"
6.Definition: emitting or reflecting very little light
"A dull glow", "Dull silver badly in need of a polish", "A dull sky"
7.Definition: lacking in liveliness or animation
"He was so dull at parties", "A dull political campaign", "A large dull impassive man", "Dull days with nothing to do", "How dull and dreary the world is", "Fell back into one of her dull moods"
8.Definition: not clear and resonant; sounding as if striking with or against something relatively soft
"The dull thud"
9.Definition: not having a sharp edge or point
"The knife was too dull to be of any use"
10.Definition: not keenly felt
"A dull throbbing", "Dull pain"
11.Definition: slow to learn or understand; lacking intellectual acuity
"Although dull at classical learning, at mathematics he was uncommonly quick"
12.Definition: so lacking in interest as to cause mental weariness
"A dull play", "His competent but dull performance"