必ず|かならずkanarazu[4]odaka (tail-high)

1. adverbalways; without exception; necessarily; certainly; without fail; positively; invariably
   あの歌うたは必かならずヒットするよ。↗

   That song's bound to be a hit.

• Synonym絶対にぜったいにNeutralNeutral word for 'absolutely'; with an affirmative like 「絶対に行く」 it matches 「必ず」, but with a negative it means 'never', the opposite.
• SynonymきっとCasualColloquial word for 'surely, most likely'; reflects the speaker's guess or resolve and sounds softer than 「必ず」.
• Synonym是非ぜひNeutralNeutral word for 'by all means', used to press a request or wish, as in 「是非来てください」.
• SynonymどうしてもCasualColloquial phrase for 'no matter what, at any cost'; with a negative it means something simply cannot be done.
• Synonym誓ってちかってWrittenWritten word with an oath-like tone, 'upon my word', as in 「誓って嘘ではない」; swears to the truth of what you say.
• Synonym必ずやかならずやWrittenEmphatic written form of 「必ず」, as in 「必ずや成功するだろう」; often pairs with conjecture and sounds more solemn.
• Synonym必定ひつじょうWrittenWritten word for what is bound to happen, as in 「必定である」; carries a Buddhist or old-fashioned flavor — say 「必ず」 in everyday speech.
• Synonym相違なくそういなくWrittenWritten phrase meaning 'no discrepancy', used in documents like 「右相違なく」; it confirms facts rather than predicting the future.
• Related決まってきまってCasualColloquial; used when something invariably happens on a given occasion, as in 「雨の日は決まって渋滞する」; stresses the regular pattern.
• Related断じてだんじてWrittenWritten and very strong; usually with a negative as in 「断じて許さない」, expressing flat refusal.
• Related常々つねづねWrittenWritten word for 'all along, in ordinary times', as in 「常々思っていた」; about what is usual, not about certainty.
• Related常につねにNeutralNeutral word meaning 'at all times', as in 「常に注意する」; stresses constancy that never changes.
• Related必然的ひつぜんてきWrittenWritten na-adjective meaning 'inevitable', as in 「必然的な結果」; academic in flavor, describing something as bound to happen.
• RelatedまさにNeutralNeutral word for 'just, exactly' or 'on the point of', as in 「まさに今」「まさにその通り」; works in both speech and writing.
• RelatedいつもCasualColloquial word for 'always, usually'; describes habitual frequency rather than the certainty of 「必ず」.
• Related絶えずたえずNeutralNeutral word meaning 'constantly, without pause', as in 「絶えず努力する」; focuses on unbroken continuity.
• Related確かにたしかにNeutralNeutral word for confirming a fact, as in 「確かに受け取った」; 「必ず」 is about something happening every time or certainly in the future.
• RelatedまさしくWrittenWritten word meaning 'just, exactly', as in 「まさしく本物だ」; affirms or identifies what something is.
• Related定めしさだめしWrittenWritten word meaning 'surely, presumably' with a conjectural nuance, as in 「定めしお困りでしょう」.
• RelatedしかとWrittenOld-fashioned and solemn, meaning 'firmly, for certain', as in 「しかと承った」; can also mean gripping tightly.
• Related定めてさだめてWrittenWritten word close to 「定めし」 in meaning 'surely, presumably'; rarely seen in modern Japanese.
• Antonym決してけっしてNeutralNeutral antonym: takes a negative and means 'never, absolutely not', the opposite direction from the affirmation of 「必ず」.
• Antonym滅多にめったにCasualColloquial antonym: with a negative it means 'rarely, seldom', the reverse of the inevitability of 「必ず」.

Use 「必ず」 by default for 'certainly, without exception'. For written emphasis choose 「必ずや」; for a conjectural 'surely' choose 「きっと」; for requests use 「是非」; for a regular pattern use 「決まって」; for 'absolutely' use 「絶対に」, and 「決して」 with a negative for 'never'. Many others are written or old-fashioned (「断じて」「相違なく」「定めし」 etc.), confirm facts (「確かに」), or describe habits (「いつも」「常に」「絶えず」).

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

1. ある事こと以外いがいの事ことの起おこる可能性かのうせいが全まったくない様子ようす。絶対ぜったいに。きっと。間違まちがいなく。
2. あること以外いがいのことをするつもりがまったくない様子ようす。絶対ぜったいに。きっと。まちがいなく。