Assassin (noun)

1. A person who kills someone for political or religious reasons.
2. A person who kills someone for payment or for hire.

Origin:

Late 16th century: from arabic āṣīsīn, plural of āṣīs "hashish user" (because of the reputation of early assassins for using the drug).

Examples:

1. He was assassinated by an unknown gunman.
2. The President"s bodyguard foiled the assassin"s attempt on his life.
3. The assassin used a rifle to carry out the attack.
4. The assassin's motive was political.
5. The assassin was caught and brought to justice.