attacker
Word family
Synonym discussion
Sense: noun/1
For noun sense 1, attacker is the most general everyday word for someone who uses violence against a person or place. Assailant is more formal and often appears in police reports or court writing. Aggressor is useful when you want to stress who started the violence or conflict, including in political or military contexts. Mugger is much narrower: it usually means someone who attacks a person in public in order to steal. A news report might say police are searching for an attacker or an assailant. If you want to stress blame, say the aggressor. If a thief hit someone for a wallet, mugger is the best choice.
Etymology
Attacker was formed in English from attack and the ending -er, which is used for a person who does an action. Attack came into English through French from an Italian verb meaning to fasten or move against.