1. [Adjective]: not keenly felt; "a dull throbbing"; "dull pain"

2. [Adjective]: emitting or reflecting very little light; "a dull glow"; "dull silver badly in need of a polish"; "a dull sky"

3. [Adjective]: not having a sharp edge or point; "the knife was too dull to be of any use"

4. [Adjective]: 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"

5. (of business) not active or brisk; "business is dull (or slow)"; "a sluggish market"

6. (of color) very low in saturation; highly diluted; "dull greens and blues"

7. darkened with overcast; "a dark day"; "a dull sky"; "a gray rainy afternoon"; "gray clouds"; "the sky was leaden and thick"

8. so lacking in interest as to cause mental weariness; "a boring evening with uninteresting people"; "the deadening effect of some routine tasks"; "a dull play"; "his competent but dull performance"; "a ho-hum speaker who couldn''t capture their attention";

9. not clear and resonant; sounding as if striking with or against something relatively soft; "the dull thud"; "thudding bullets"

10. slow to learn or understand; lacking intellectual acuity; "so dense he never understands anything I say to him"; "never met anyone quite so dim"; "although dull at classical learning, at mathematics he was uncommonly quick"- Thackeray; "dumb officials mak

11. being or made softer or less loud or clear; "the dull boom of distant breaking waves"; "muffled drums"; "the muffled noises of the street"; "muted trumpets"

12. blunted in responsiveness or sensibility; "a dull gaze"; "so exhausted she was dull to what went on about her"- Willa Cather

13. [Verb]: make numb or insensitive; "The shock numbed her senses"

14. [Verb]: make less lively or vigorous; "Middle age dulled her appetite for travel"

15. [Verb]: become less interesting or attractive

16. [Verb]: make dull or blunt; "Too much cutting dulls the knife''s edge"

17. [Verb]: deaden (a sound or noise), especially by wrapping

18. [Verb]: become dull or lusterless in appearance; lose shine or brightness; "the varnished table top dulled with time"

19. [Verb]: make dull in appearance; "Age had dulled the surface"

1. inactive

2. flat

3. mat

4. matt

5. matte

6. matted

7. lackluster

8. lacklustre

9. lusterless

10. lustreless

11. unsaturated

12. stupid

13. cloudy

14. blunt

15. blunted

16. dulled

17. edgeless

18. unsharpened

19. deadened

20. arid

21. desiccate

22. desiccated

23. bovine

24. drab

25. dreary

26. heavy

27. leaden

28. humdrum

29. monotonous

30. lackluster

31. lacklustre

32. lusterless

33. lustreless

34. uninteresting

35. soft

36. unreverberant

37. nonresonant

38. insensitive

1. sharpen

2. bright

3. sharp

4. sharp

5. lively