
neck
head
dismissal (from a job); firing; sacking
「首」 has other readings with different meanings.
首が痛くて動かせません。
My neck hurts and I can't move it.
不思議な話を聞いて首をかしげた。
I tilted my head at the strange story.
首がとても痛くて辛いです。
The soreness in my neck is really getting to me.