Kill-this can be used to talk about the cause of death of a person or any other living thing. This can be intentional or unintentional.
- He killed the spider in the bathroom.
- The woman was killed in a hit and run accident.
- The lion hunted and killed the zebra.
Murder-this is used to talk the intentional cause of death of another human being.
- The police think she murdered her husband.
- He said he will murder me if I don’t give him the money.
- They were murdered by they’re neighbour, he shot them all.
Assassinate-this is the murder of an important or prominent person like a president or a political activist for religious or political reasons.
- There are plans to assassinate the president.
- John F. Kennedy was assassinated in Texas, he was shot twice.
- The assassination of Malcolm X occurred in 1965, he was shot 16 times.