—adj. 1. not sharp; blunt: a dull knife. 2. causing boredom; tedious; uninteresting: a dull sermon. 3. not lively or spirited; listless.
4. not bright, intense, or clear; dim: a dull day; a dull sound. 5. having very little depth of color; lacking in richness or intensity of color.
6. slow in motion or action; not brisk; sluggish: a dull day in the stock market. 7. mentally slow; lacking brightness of mind; somewhat stupid; obtuse.
8. lacking keenness of perception in the senses or feelings; insensible; unfeeling.
9. not intense or acute: a dull pain.