expression, godan verb (-ru)
cut one's hand
Literal meaning: to sustain a cut on the hand. Not an idiom.
包丁で手を切ってしまった。
I accidentally cut my hand with a kitchen knife.
expression, godan verb (-ru)
cut ties; break off relations; part ways
Idiomatic: to sever a relationship or connection with someone, often with a sense of finality. Commonly used with ～と.
彼とはもう手を切った。
I've already cut ties with him.
あの会社とは手を切るべきだ。
You should break off relations with that company.