必: must

必 zhēng

noun | verb
: journey; trip; expedition
: to go on long campaign; to attack

必ず | かならず kanarazu

adverb
: always; without exception
: necessarily
: certainly; without fail; positively; invariably

必ずや | かならずや kanarazuya

adverb
: certainly; surely; definitely

必ずしも | かならずしも kanarazushimo

adverb
: (not) always; (not) necessarily; (not) all; (not) entirely

必須[须] bi4xu1: to have to; must; compulsory; necessarily
[必須 | ひっす hissu: indispensable; required]

必要 bi4yao4: necessary; essential; indispensable; required
[ひつよう hitsuyou: necessary; essential; requirement]

必然 bi4ran2: inevitable; certain; necessity [ひつぜん hitsuzen]

必定 bi4ding4: to be bound to; to be sure to; certainly
[ひつじょう hitsujou: inevitably; certainly]

必修 bi4xiu1: a required course
[ひっしゅう hisshuu: required (subject)]

不必 bu4bi4: need not; does not have to; not necessarily

不必要 bu4 bi4 yao4: unnecessary; needless [ふひつよう fuhitsuyou: unnecessary; undesired]

未必 wei4bi4: not necessarily; maybe not

何必 he2bi4: there is no need; why should

勢[势]必 shi4bi4: to be bound to; undoubtedly will

務[务]必 wu4bi4: must; to need to; to be sure to

Japanese expression / idiom
必要なし | ひつようなし hitsuyou nashi
: not required

必要とする | ひつようとする hitsuyou tosuru
to need; to call for; to require

一発必中 | いっぱつひっちゅう ippatsu hicchuu
: success on the first try (attempt)

後手必敗 | ごてひっぱい gote hippai
: Defeat is inevitable for one who goes second. Being slow to take action inevitably leads to defeat

先手必勝 | せんてひっしょう sente hisshou
: victory goes to the one who makes the first move; being quick to take action leads to victory; the early bird gets the worm

*驕兵必敗 | きょうへいひっぱい kyouhei hippai
: Defeat is inevitable for an overconfident army. Being arrogant and overconfident inevitably leads to defeat (failure). Pride comes before a fall

必要は発明の母 | ひつようははつめいのはは hitsuyou wa hatsumei no haha
: necessity is the mother of invention

積善の家には必ず余慶あり | せきぜんのいえにはかならずよけいあり sekizen no ieni wa kanarazu yokeiari
: one’s good deeds shall be repaid even to one’s descendants

生有る者は必ず死有り | せいあるものはかならずしあり seiarumono wa kanarazu shiari
: No mortal escapes death

Chinese idiom / proverb
事必有兆 shi4 bi4 you3 zhao4
: future events always have an omen

勢在必得 [势在必得] shi4 zai4 bi4 de2
: to be determined to win

*驕兵必敗 [骄兵必败] jiao1 bing1 bi4 bai4
: lit. an arrogant army is bound to lose; fig. pride goes before a fall

三人行，則必有我師[师] san1 ren2 xing2 , ze2 bi4 you3 wo3 shi1
: lit. if three walk together, one can be my teacher (from the Analects of Confucius). You have something to learn from everyone

兩虎相爭，必有一傷 [两虎相争，必有一伤] liang3 hu3 xiang1 zheng1 , bi4 you3 yi1 shang1
: when two tigers fight, one will get injured; if you start a war, someone is bound to get hurt

有其師，必有其徒 [有其师，必有其徒] you3 qi2 shi1 , bi4 you3 qi2 tu2
: As the teacher, so the pupil.

有其父必有其子 you3 qi2 fu4 bi4 you3 qi2 zi3
: like father, like son

早知今日何必當初 [早知今日何必当初] zao3 zhi1 jin1 ri4 he2 bi4 dang1 chu1
: if I (you, she, he…) had known it would come to this, I (you, she, he…) would not have acted so. To regret vainly one’s past behavior

空穴來風未必無因 [空穴来风未必无因] kong4 xue2 lai2 feng1 wei4 bi4 wu2 yin1
: wind does not come from an empty cave without reason; there’s no smoke without fire

車到山前必有路，船到橋頭自然直 [车到山前必有路，船到桥头自然直] che1 dao4 shan1 qian2 bi4 you3 lu4 , chuan2 dao4 qiao2 tou2 zi4 ran2 zhi2
: lit. When we get to the mountain, there will be a way through. When the boat gets to the pier-head, it will straighten with the current. fig. Everything will turn out for the best. Let’s worry about it when it happens.

大難不死，必有後福 [大难不死，必有后福] da4 nan4 bu4 si3 , bi4 you3 hou4 fu2
: one is bound for good fortune after surviving a great disaster