なければ
無ければ
nakereba

Expression

1. if (it) doesn't exist; if there is no ...; if (one) doesn't have ...

Usually Written in Kana
みずがなければ、何者なにものもこの地球ちきゅうじょうにはきられないだろう。
mizuga nakereba nanimonomo kono chikyūjōniwa ikirarenaidarō.
Without water, nothing could live on this earth.
Auxiliary Verb
Expression

2. if not ...; unless ...

Usually Written in Kana
いそがなければ、学校がっこう遅刻ちこくしますよ。
isoganakereba gakkōni chikoku shimasuyo.
Unless you hurry, you will be late for school.
Auxiliary Verb
Expression

3. have to ...; must ...

Abbreviation
Usually Written in Kana
Related to なければならない
いそがなければ、急行きゅうこうおくれるぞ。
isoganakereba kyūkōni noriokureruzo.
You must hurry up, or you will miss the express.