Robert Sternberg saw three main elements in hatred:

• a negation of intimacy, by creating distance when closeness had become threatening;
• an infusion of passion, such as fear or anger;
• a decision to devalue a previously valued object.

The front-facing fist 👊: Threatening, intense, replicable (most people have hands)

The down-facing knife 🔪: sharp, cold, calculated

There are also very specific symbols of hatred, like the swastika and the Nazi salute, white-hooded robes and burning crosses, the flag of the Daesh, the Z of the RAF for the West et al., but all of those are tied to certain ideologies and cultures and might not make any sense outside of relevant situations.