Attack, assault, onslaught and onset denote an attempt made on another or on others to injure, destroy, or defame.
An attack may be upon the physical person or it may be upon the character, the reputation, or the writings of a person or persons; it often suggests animosity or definite enmity as its cause, but it may imply motives as various as wanton cruelty, partisan feeling, or a critical intention.
Assault implies more violence, more malice or viciousness, and often the infliction of greater damage or less reparable damage than attack. However, an assault upon the person is legally an apparently violent attempt or a willful offer with force or violence to injure or hurt that person physically. When the hurt has been inflicted, the precise legal term for the act is assault and battery.
Rape is sometimes specifically called an assault. In military language an assault is sometimes distinguished from an attack upon the enemy, the former term being applied only to the last phase of an attack or offensive movement, when the aggressors close upon their opponents and the issue is determined.
Usually assault and attack are not clearly distinguishable except in emphasis; thus, an assault upon a person’s character suggests violent emotion (as hatred or vindictiveness); an attack upon a person’s character need not imply strong feeling as its motive.
Onslaught suggests a vigorous and destructive method of attack; it usually implies an attempt to overwhelm by force of momentum or of numbers or by the fury of the assault.
Onset is applicable not only to the first furious rush that initiates an attack (as an offensive movement, an act of aggression, or a fit of illness) but to any such succeeding rush that marks a renewal of vigor in the attack.