いい加減|いいかげんiikagen[0]heiban (flat)

1. na-adjectiveirresponsible; perfunctory; careless
   いいかげんな話はなしはやめろ。↗

   Don't give me that!

   いいかげんに仕事しごとをするな。↗

   Don't do the job just any old way.
2. na-adjectivelukewarm; half-baked; halfhearted; vague
3. na-adjective, adverb(already) enoughused to express one's wish for something to end
   この静しずかな生活せいかつにはいい加減かげん飽あきてしまった。↗

   I'm about tired of this quiet life.
4. adverbconsiderably; quite; rather; pretty
   スミス夫妻ふさいのテレビにはいいかげんうんざりです。↗

   He's just about had enough of the Smiths' TV.

• Synonym無責任むせきにんNeutralRefers to irresponsibility, as in 「無責任な発言」; 「いい加減」 centers on being slapdash and perfunctory.
• SynonymでたらめNeutralNonsense talk or a jumbled, unsystematic state, as in 「でたらめな話」「でたらめな配置」.
• Synonym軽率けいそつNeutralRashness, as in 「軽率な行動」; stresses acting without due consideration.
• SynonymぞんざいCasualColloquial. Careless, rough handling of people or things, as in 「ぞんざいな扱い」「ぞんざいな口調」.
• Synonym通り一遍とおりいっぺんNeutralGoing through the motions, as in 「通り一遍の挨拶」; stresses doing only what is on the surface.
• Synonym粗略そりゃくNeutralNeglect; treating something as not worth proper attention, as in 「粗略に扱う」.
• SynonymちゃらんぽらんCasualColloquial. A careless, devil-may-care manner, as in 「ちゃらんぽらんな性格」.
• Synonym出任せでまかせNeutralTalking off the top of one's head, as in 「口から出任せ」; stresses speaking carelessly without thinking.
• Synonym無考えむかんがえNeutralThoughtless, acting without consideration; used less often — 「軽率」 is the usual choice.
• SynonymおざなりWrittenWritten/formal. Perfunctory handling just to get through the moment, as in 「おざなりな対応」; stresses going through the motions.
• Synonym粗忽そこつWrittenWritten/formal word for carelessness, as in 「粗忽者」.
• Related無関心むかんしんNeutralIndifference, as in 「政治に無関心」; the point is not caring about something, not doing things half-heartedly.
• RelatedそそっかしいCasualColloquial adjective for a rash, scatterbrained person, as in 「そそっかしい人」; stresses a careless character.
• Related皮相ひそうWrittenWritten/formal word for being superficial, as in 「皮相な見方」.
• Related無頓着むとんちゃくNeutralNot being particular about something, as in 「服装に無頓着」; stresses simply not caring.
• Relatedお構いなしおかまいなしCasualColloquial. Paying no heed, as in 「人の迷惑もお構いなし」; stresses disregarding others.
• RelatedうかつNeutralA careless oversight, as in 「うかつだった」; often used in hindsight, regretting one's slip.
• Related向こう見ずむこうみずNeutralRecklessness, as in 「向こう見ずな行動」; stresses plunging ahead regardless of danger.
• RelatedむやみNeutralDoing something indiscriminately, as in 「むやみに使う」; stresses lack of restraint.

Use 「いい加減」 for doing things in a slapdash, irresponsible way, as in 「いい加減な仕事」; it also means 'enough, stop it', as in 「いい加減にしろ」. For merely going through the motions say 「おざなり」, for talking nonsense 「でたらめ」, and for plain irresponsibility 「無責任」.

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

1. 相当そうとう。かなり。
2. なげやりなさま。無責任むせきにんなさま。