Contraction of なくては(ならない) (nakute wa (naranai)).
なくちゃ • (-nakucha) (appended after imperfective form)
- (informal) must, have to
- もう行かなくちゃ。
- Mō ikanakucha.
- I have to go now.
- (informal) if one doesn't...
- 勉強しなくちゃ試験に受からない。
- Benkyōshinakucha shiken ni ukaranai.
- If you don’t study, you will fail the exam.