godan verb (-u)
hate each other; hate mutually
Describes a mutual hatred between two or more parties. The subject is typically plural or a collective noun.
See also: 憎しみ合う
あの二人は昔から憎み合っている。
Those two have hated each other for a long time.
憎み合うよりも、話
Let's resolve this through discussion rather than hating each other.