not sharp; blunt

a dull knife.

causing boredom; tedious; uninteresting

a dull sermon.

not lively or spirited; listless.

not bright, intense, or clear; dim

a dull day; a dull sound.

having very little depth of color; lacking in richness or intensity of color.

slow in motion or action; not brisk; sluggish

a dull day in the stock market.

mentally slow; lacking brightness of mind; somewhat stupid; obtuse.

lacking keenness of perception in the senses or feelings; insensible; unfeeling.

not intense or acute

a dull pain.

to make or become dull.

noun

action , liveliness , interest

noun

flatness , sameness , routine , uninterestingness , aridity , dryness , drabness , tediousness , commonplaceness , tedium , monotomy , dreariness , insipidity , vapidity , staleness , lifelessness , familiarity , boredom , slowness , stupidness , insensibility , slowwittedness , hebetude , languidness , languor , lassitude , leadenness , listlessness , sluggishness , stupor , torpidity , torpor , asepticism , blandness , colorlessness , flavorlessness , insipidness , jejuneness , sterileness , sterility , stodginess , vapidness , weariness , apathy , bluntness , evenness , lethargy , monotony , spiritlessness