dull

lacking in liveliness or animation“he was so dull at parties”

emitting or reflecting very little light“a dull glow”

so lacking in interest as to cause mental weariness“a boring evening with uninteresting people”

slow to learn or understand; lacking intellectual acuity“so dense he never understands anything I say to him”

not having a sharp edge or point“the knife was too dull to be of any use”

being or made softer or less loud or clear“the dull boom of distant breaking waves”

(of business) not active or brisk“business is dull (or slow)”

not clear and resonant; sounding as if striking with or against something relatively soft“the dull thud”

darkened with overcast“a dull sky”

(of color) very low in saturation; highly diluted“dull greens and blues”

not keenly felt“a dull throbbing”

blunted in responsiveness or sensibility“a dull gaze”

deaden (a sound or noise), especially by wrapping

make numb or insensitive“The shock numbed her senses”

make dull or blunt“Too much cutting dulls the knife's edge”

become less interesting or attractive

make dull in appearance“Age had dulled the surface”

become dull or lusterless in appearance; lose shine or brightness“the varnished table top dulled with time”

make less lively or vigorous“Middle age dulled her appetite for travel”