To Get Fired
To Get Sacked
expression, godan verb
The になる part means "to become," so literally this means "to become neck." If you think about it, when something becomes neck, it has to do with you getting your head cut off (at the neck). But, in today's modern society we don't do that too often. Instead, this means you lose your job, aka to get fired.
This word contains the reading you learned with the kanji. Everything else is hiragana.
しごとを首になる
to be fired from one's job
バイトを首になる
to be fired from one's part time job
会社を首になる
to be fired from the company
先月、会社を首になりました。
Last month, I was fired from the company.
首にならないように、がんばります。
I will try my best not to get fired.
そんなことしたら、バイト首になるよ！
If you do such a thing, you'll lose your part-time job!