Explanation
Express a necessity or obligation; 'must', 'have to'.
Formation
Verb-casual (negative form without い) + なきゃいけない
Detailed explanation
The ～なきゃいけない grammar point is used to express a sense of necessity or obligation, similar to saying 'must' or 'have to' in English. It is a casual and more colloquial form of the ～なければいけない grammar point. The formation is different for verbs, but it is not used with い-adjectives, な-adjectives, or nouns.
Examples
Ashita made ni shukudai wo owaranakya ikenai.
I have to finish my homework by tomorrow.
Mou sugu dekakeru kara, isoide junbi shinakya ikenai.
We're leaving soon, so I have to hurry and get ready.
Kono purojekuto wa raishuu teishutsu shinakya ikenai.
I must submit this project by next week.
Densha ni noru mae ni, kippu wo kawanakya ikenai.
I have to buy a ticket before getting on the train.
Practice
Grammar content sourced from hanabira.org.