Assaulter

a sudden, violent attack; onslaught:
an assault on tradition.
Law. an unlawful physical attack upon another; an attempt or offer to do violence to another, with or without battery, as by holding a stone or club in a threatening manner.
Military. the stage of close combat in an attack.
1 .
to make an assault upon; attack; assail.
Historical Examples

Again concealing the weapon within his doublet, a sudden realisation of the necessity for speed overcame the assaulter.
The Strong Arm Robert Barr

Weaponless, the assaulter had used his hands, and now with a knee upon Mexia’s breast he strove to throttle him.
Sir Mortimer Mary Johnston

I have friends who will find means to succour and protect you, be who will your assaulter!’
The Wanderer (Volume 4 of 5) Fanny Burney

noun
a violent attack, either physical or verbal
(law) an intentional or reckless act that causes another person to expect to be subjected to immediate and unlawful violence Compare battery (sense 4), assault and battery

the culmination of a military attack, in which fighting takes place at close quarters
(as modifier): assault troops

rape or attempted rape
verb (transitive)
to make an assault upon
to rape or attempt to rape
n.

late 14c., earlier asaut (c.1200), from Old French asaut, assaut “an attack, an assault, attacking forces” (12c.), from Vulgar Latin *adsaltus “attack, assault,” from ad “to” (see ad-) + Latin saltus “a leap,” from salire “to leap, spring” (see assail). In law by 1580s; historically, assault includes menacing words or actions; battery is an actual blow.
v.

early 15c., from Middle French asauter, assauter, from Vulgar Latin *assaltare (see assault (n.)). Related: Assaulted; assaulting.