簡易|かんいkan'i[0]heiban (flat)

1. na-adjective, nounsimple; simplified
2. na-adjective, nouneasy; plain

• SynonymやさしいNeutralAn adjective for questions or texts that are easy and not difficult, as in 「易しい問題」; 「簡易」 is about a simplified, streamlined form or method.
• Synonym生易しいなまやさしいNeutralUsually takes a negative, meaning 'not so simple', as in 「生易しい仕事ではない」; 「簡易」 has no such restriction to negatives.
• Synonym簡単かんたんNeutralThe most general word for simple and easy, fine in speech and writing, as in 「簡単な料理」; 「簡易」 is more written in flavour and often forms compounds.
• SynonymシンプルNeutralA loanword for something structurally uncomplicated or plain and unadorned, as in 「シンプルな仕組み」; 「簡易」 stresses simplification and convenience.
• SynonymたやすいWrittenA written adjective for something done with no effort, as in 「たやすく解決する」; 「簡易」 instead stresses a simplified form.
• Synonym平易へいいWrittenA written word for writing or explanations that are plain and easy to follow, as in 「平易な文章」; 「簡易」 is about a simplified, convenient method.
• Synonym容易よういWrittenA written word for something not hard to do, as in 「容易ではない」; 「簡易」 stresses the simplified form or method instead.
• Synonym手軽てがるNeutralFor things that take little effort and are handy, as in 「手軽な朝食」; common in speech, while 「簡易」 is more written and often forms compounds.
• Synonym楽らくNeutralFor feeling relaxed and unburdened, as in 「楽な仕事」; it is about physical or mental ease, while 「簡易」 is about a simple form.
• Synonym簡便かんべんWrittenA written word for simple and convenient, as in 「簡便な方法」; 「簡易」 stresses simplification and does not especially stress convenience.
• Synonym安直あんちょくNeutralFor taking the easy way out or being cheap, as in 「安直な考え」; often derogatory, a shade 「簡易」 does not carry.
• SynonymイージーCasualA colloquial loanword for easy, also for careless or sloppy, as in 「イージーミス」; 「簡易」 has no sense of sloppiness.
• Synonym安易あんいNeutralFor hasty, easy-way-out thinking, as in 「安易な判断」; often derogatory, while 「簡易」 simply means simplified, with no negative shade.
• SynonymやすいNeutralMostly a suffix meaning easy to do, as in 「使いやすい」; on its own in the sense of easy it now sounds dated, and 「簡易」 never works as a suffix.
• Synonym簡略かんりゃくWrittenA written word for cutting out complexity, as in 「簡略化する」; it stresses omission, while 「簡易」 stresses being handy and saving effort.
• Synonym単純たんじゅんNeutralFor structures that are uncomplicated, as in 「単純な構造」; it can also mean simple-minded, while 「簡易」 is about a handy, simplified form or method.
• Synonym造作ないぞうさないWrittenA written phrase for something that takes no trouble at all, now rare; in daily speech 「簡単」 is used, while 「簡易」 stresses a simplified form.
• SynonymわけないCasualColloquial for something requiring no effort at all, as in 「訳ない仕事」; it can also mean 'impossible', a use 「簡易」 lacks.
• Synonymお安いおやすいCasualColloquial, mostly in 「お安い御用だ」, for a trivial task done gladly; 「簡易」 is not used this way.
• SynonymちょろいCasualSlang for a piece of cake, often with a dismissive edge, and also for people easily fooled; 「簡易」 is a neutral, written-flavoured word.
• Synonym軽易けいいWrittenA written word for light and easy, now rarely used; in daily language 「手軽」 is used, while 「簡易」 stresses a simplified form.
• Synonym楽チンらくチンCasualSlang for easy and comfortable, with a friendly, casual feel; 「簡易」 is a neutral word that leans written.
• RelatedプレーンNeutralA loanword for plain, unflavoured or unadorned things, as in 「プレーンヨーグルト」; mostly for food, a sense 「簡易」 does not have.
• Related平明へいめいWrittenA written word for prose that is plain and clear, used mainly in evaluating style, and also meaning daybreak; 「簡易」 is about saving effort.
• Related簡明かんめいWrittenA written word for concise, clear expression, as in 「簡明な説明」; it is about how things are expressed, while 「簡易」 is about a simplified form or method.
• RelatedわかりやすいNeutralAn adjective for something easy to understand, as in 「分かりやすい説明」; it concerns comprehension only, while 「簡易」 is about a simplified, convenient way of doing things.
• Related単簡たんかんWrittenA written word for simple, now rarely used; in daily language 「簡単」 is used, while 「簡易」 stresses a simplified form.
• Antonym複雑ふくざつNeutralFor things so tangled they are hard to understand or handle; the direct opposite of 「簡易」 in terms of simplicity.
• Antonym本格的ほんかくてきNeutralFor the genuine, full-scale version done by proper methods, as in 「本格的な料理」; the opposite of 「簡易」 as a simplified version.

Use 「簡易」 for simplified, streamlined things and methods, as in 「簡易書留」 or 「簡易な検査」. For plain simplicity in everyday speech, 「簡単」 is the default; 「易しい」 suits easy questions or texts, and 「手軽」 things that are handy and effortless. Many alternatives are colloquial (「ちょろい」, 「楽チン」) or written (「平易」, 「簡便」), and some carry negative shades (「安易」, 「安直」). The opposites are 「複雑」 and 「本格的」.

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

1. た易やすく、簡単かんたんな様子ようす。