noun
assailant
uh-SAY-lunt/əˈseɪlənt/
A person who attacks someone violently.
The assailant lunges with a raised fist as the man shields his head.

Etymology
The underlying image is of leaping toward someone, which became a way to describe attacking violently. The participial ending identifies the person carrying out that attack.
In context
By the fact that the man was attacked with an Italian stiletto, it would seem that his assailant was a fellow-countryman
More examples
- The assailant fled before help arrived.
- Security footage showed two assailants.
- The victim could not identify the masked assailant.
Forms
assailant · assailants
Similar words
- attacker
- The everyday equivalent, also used outside personal violence.
- aggressor
- Initiates conflict without necessarily committing a particular violent attack.