► 副詞
嘸 [(1)さぞ] [さぞ～う] [liter] meaning: must rank: 3
☆ 子供の時に両親を失うなんて、さぞ辛かったことだろう ⇨ It must’ve been extremely painful to lose both parents when he/she was a child (☛ Empathize with someone by imagining something one has not experienced oneself)
嘸かし [(1)さぞかし] [liter] meaning: must rank: 4
☆ 彼は孤児なので、さぞかし悲しい思いをしたことだろう ⇨ He was an orphan, so he must have gone through a lot of heartbreaks
► 助動詞
可き [(1)べき] [liter] meaning: must rank: 2
☆ あの会社に投資するべきではなかった ⇨ I shouldn’t have invested in that company (☛ 連体形 of 可し)
☆ 子供にそういうことを言うべきではない ⇨ You shouldn’t say something like that to a child (☛ 連体形 of 可し)
☆ 実験は今すぐ止めるべきだ ⇨ We must stop the experiment right now (☛ 連体形 of 可し)
☆ 試合は中止するべきだった ⇨ We should’ve canceled the game (☛ 連体形 of 可し)
べし [(1)べし] [liter] meaning: must rank: 3
☆ 注意すべし ⇨ You must be careful
► 成句
いけない [いけない] [ないといけない] meaning: must rank: 1
☆ もう行かないといけない ⇨ I have to go now
いけない [いけない] [なくてはいけない] meaning: must rank: 1
☆ もう帰らなくてはいけない ⇨ I need to go home
☆ 相手の気持ちを考えなくてはいけない ⇨ You have to think about what the feelings of the other person
☆ 費用を節減しなくてはいけない ⇨ We need to reduce our expenses
いけない [いけない] [なければいけない] meaning: must rank: 1
☆ 早急に対策を立てなければいけない ⇨ We need to come up with a countermeasure quickly
決まる [きまる] [決まっている] [coll] meaning: must rank: 1
☆ 彼の約束なんて嘘に決まってるじゃない ⇨ His promise is bound to be a lie (☛ Typically implies the speaker is not happy with the result)
☆ 彼はステロイドを使っているに決まっている ⇨ It must be, I’m sure, that he is using steroid (☛ Typically implies the speaker is not happy with the result)
いけない [いけない] [なきゃいけない] [coll] meaning: must rank: 2
☆ もっと勉強しなきゃいけない ⇨ I have to study more
☆ 急がなきゃいけない ⇨ We need to hurry up
いけない [いけない] [なくちゃいけない] [coll] meaning: must rank: 2
☆ 子供を迎えに行かなくちゃいけない ⇨ I have to go pick up my child
☆ もう帰らなくちゃいけない ⇨ I need to go home (☛ “ちゃ” is a colloquial contraction of “ては”)
得ない [(1)えない] [ざるを得ない] [liter] meaning: must rank: 2
☆ この計画は中止せざるを得ない ⇨ We have no choice but aborting this project
☆ 代替案を考えざるを得ない ⇨ We have no choice but to come up with an alternative plan
☆ 彼らの要求を飲まざるを得ない ⇨ We have no choice but accept their demands
☆ 悪天候のため運行を停止せざるを得ない ⇨ Due to the bad weather we have no choice but to stop the operation
なきゃ [(1)なきゃ] [なければ] [coll] meaning: must rank: 2
☆ もう行かなきゃ ⇨ I gotta go now (☛ いけない is omitted at the end)
なくちゃ [(1)なくちゃ] [なくては] [coll] [peer] meaning: must rank: 2
☆ もう行かなくちゃ ⇨ I gotta go now (☛ いけない is omitted at the end)
なくっちゃ [(1)なくっちゃ] [なくては] [coll] [peer] meaning: must rank: 2
☆ あなたもっと頑張らなくっちゃ ⇨ You have to work harder (☛ いけない is omitted at the end)
☆ もう行かなくっちゃ ⇨ I gotta go now (☛ いけない is omitted at the end)
なくては [(1)なくてわ] [ない＋ては] [liter] meaning: must rank: 2
☆ もう行かなくては ⇨ I must go now
ならない [(2)ならない] [なくてはならない] [liter] meaning: must rank: 2
☆ 明日までに書類を提出しなくてはならない ⇨ I have to submit the documents by tomorrow
ならない [(2)ならない] [なければならない] [liter] meaning: must rank: 2
☆ オイルは１万キロごとに交換しなければならない ⇨ The oil must be changed every 10K km
☆ 我々は国を侵略者から守らなければならない ⇨ We need to defend our country from invaders
☆ 明日までに書類を提出しなければならない ⇨ I have to submit the documents by tomorrow
いけない [いけない] [なけりゃいけない] [coll] meaning: must rank: 3
☆
ならない [(2)ならない] [なきゃならない] [coll] meaning: must rank: 3
☆ 電気代を払わなきゃならない ⇨ I need to pay the electricity bill
ならぬ [(2)ならぬ] [てはならぬ] [ならない] [arch] meaning: must rank: 3
☆ 中を見てはならぬ ⇨ Don’t look what’s inside (☛ Used often in period dramas)
ならぬ [(2)ならぬ] [ねばならぬ] [ならない] [arch] meaning: must rank: 3
☆ もう行かねばならぬ ⇨ I must go already (☛ Used often in period dramas)
► 名詞
筈 [(2)はず] meaning: must rank: 1
☆ それは彼も知っている筈だ ⇨ He is supposed to know that, he must know that
☆ そんな筈は無い ⇨ That can’t be (true)
☆ 止めろと何度も言った筈だ ⇨ (It is certain that) I told you many times to stop
必携 [ひっけい] meaning: must rank: 3
☆ 投資家必携の書 ⇨ A book all the investors should have on their sides (☛ Must-have)
必見 [ひっけん] meaning: must rank: 3
☆ 必見の映画 ⇨ A must-see movie
必勝 [ひっしょう] meaning: must rank: 3
☆ 彼等は次の試合に必勝を期している ⇨ They are determined to win the next game
必需品 [ひつじゅひん] meaning: must rank: 3
☆ 日本では傘は必需品だ ⇨ Umbrellas are must-haves in Japan