How to say "dull" in Japanese

• 鈍いにぶいJLPT N2approx.Common
  i-adjectiveCovers the physical sense: a blade, edge, or point that is dull rather than sharp — the word for a knife that needs sharpening. It corresponds to English 'blunt' as much as to 'dull'.
• 退屈たいくつJLPT N3approx.Common
  na-adjective, nounDull in the sense of boring or uninteresting: a lecture, book, or afternoon that drags. Use it when the problem is tedium — something that fails to hold your interest.
  カクテルパーティーは退屈たいくつなときもある。↗

  Cocktail parties can be boring.
• 鈍感どんかんJLPT N1approx.Common
  na-adjective, nounDull in the sense of insensitive: a person slow to pick up on other people's feelings or on hints, thick-skinned where sensitivity is called for. It characterizes people, not things.
  概がいしてエリート達たちは批判ひはんに対たいして鈍感どんかんである。↗

  On the whole, the elite are not sensitive to criticism.
• 味気ないあじけないCommon
  i-adjectiveDull in the sense of insipid or wearisome: something dreary and flavorless because it lacks charm or appeal, such as drab daily routine. The nuance is flatness that wears you down.
  趣味しゅみがないと生活せいかつがあじけないものになるかもしれない。↗

  If one does not have a hobby, his life may be desolate.
• 鈍どんCommon
  na-adjective, nounDull in the sense of slow-witted or stupid: dullness of the mind rather than of a blade or of an activity. It paints a person whose brain is dull and slow.

Use 「鈍い」 for a dull blade or edge, 退屈 for something boring, 鈍感 for an insensitive or thick-skinned person, 「味気ない」 for what is insipid or dreary, and 鈍 for slowness or dullness of mind.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 鈍いにぶいdull (e.g. a knife)
• 退屈たいくつtedious
• 鈍感どんかんthickheaded
• 味気ないあじけないwearisome
• 鈍どんdull
• つまらないdull
• 緩慢かんまんslow
• 鈍らすにぶらすto blunt
• つまんないboring
• だるいsluggish
• ダルdull
• しょぼいshabby
• とろいdull
• 無味乾燥むみかんそうdull
• 不活発ふかっぱつdull
• とろくさいdull
• つまらぬdull
• つまらんdull
• 冴えないさえないdull
• 味も素っ気もないあじもそっけもないdull
• なまくらblunt (e.g. sword)
• 禿びるちびるto get blunt
• 一本調子いっぽんぢょうしmonotone
• 索然さくぜんboring
• 曲の無いきょくのないuninteresting
• 切れが悪いきれがわるいthick
• 振るわないふるわないin a bad way
• 芸のないげいのないuninspiring
• 頭の回転が遅いあたまのかいてんがおそいslow-witted
• 気の抜けたきのぬけたinsipid
• 間延びしたまのびしたslow
• 愚鈍ぐどんstupid
• まだるい(frustratingly) slow
• 千編一律せんぺんいちりつmonotonous
• パッとしないunimpressive
• 芸がないげいがないlacking skill
• まだるっこい(frustratingly) slow
• まだるっこしい(frustratingly) slow
• 砂を噛むようすなをかむようtasteless
• だりぃsluggish
• ばかstupid
• 寒いさむいuninteresting (esp. joke)
• 暗いくらいdark (in colour)
• 大味おおあじdull
• 平板へいばんmonotonous
• 無味むみuninteresting
• 不景気ふけいきpoor (business)
• 閑散かんさんinactive (business, trade, etc.)
• どんよりheavy
• ぬるま湯ぬるまゆcomfortable
• 無趣味むしゅみtasteless
• 暇ひまslow (business)
• しょっぱいinferior